Book summary “The ascent of money”: summary

Introduction

You live in a world built on financial mechanisms that you likely misunderstand or resent. When markets crash or banks fail, you hear finance condemned as a parasitic game played by elites at your expense. This hostility stems from widespread financial illiteracy that leaves you vulnerable to debt traps and economic shocks. You treat money as a static commodity rather than recognizing it as a complex evolutionary technology.

Niall Ferguson argues in The Ascent of Money that financial history is the hidden engine of human progress. Civilization did not advance solely through technological inventions or political revolutions. It grew because humans invented ways to translate trust into credit, manage catastrophic risk, and mobilize capital across oceans and centuries.

Financial history is the evolutionary engine of human progress, transforming trust into credit, debt, risk management, and global prosperity.

The book explores six core pillars that constructed the modern economic world. You will discover how these institutions evolved and how they shape your daily financial reality.

• How did pieces of paper replace precious metals as the foundation of global trade?
• Why do sovereign bond markets hold the power to overthrow governments?
• What causes joint stock corporations to repeatedly trigger speculative manias and market crashes?
• How do insurance and welfare systems tame the unpredictable hazards of human life?
• In what ways does real estate finance create both broad household wealth and catastrophic systemic meltdowns?
• Where do globalization and international capital flows generate prosperity before breeding geopolitical conflict?

You will trace these developments from the ancient clay tablets of Mesopotamia to the digital trading floors of the twenty-first century. By understanding the origins of money, debt, equities, insurance, real estate, and globalization, you gain the perspective needed to navigate the recurring crises of the modern economy.

1. From Trust to Inflation

Money is essentially trust inscribed on various mediums rather than physical metal, and excessive extraction of precious metals triggers destructive resource curses.

The Money Mountain

An abundance of precious metals does not make a nation wealthy; instead, it can trigger severe inflation and act as a resource curse. When the Spanish conquistadors extracted massive quantities of silver from mines like Cerro Rico, the massive influx of metal caused purchasing power to collapse. This phenomenon, known as the price revolution, reduced incentives for productive economic activity and fueled inflation while enriching the crown.

Francisco Pizarro conquered the Inca Empire and exploited the silver mountain of Cerro Rico at Potosí, which yielded massive amounts of silver shipped to Spain. The peak rose 4,824 metres above sea level. The Incas had collected 13,420 pounds of 22 carat gold and 26,000 pounds of pure silver to buy Atahuallpa's freedom. Cerro Rico yielded 45,000 tons of pure silver between 1556 and 1783. Spanish fleets transported 170 tons of silver across the Atlantic annually.

Money has evolved from physical commodities and metallic coins to clay tokens, paper banknotes, and electronic records. The core of money is the belief and trust in the issuer or the institution honoring the transactions. Ancient Mesopotamian merchants and kings used clay tablets to record transactions involving commodities like barley or silver, functioning similarly to modern promissory notes. Ordinary Americans hold only 11 per cent of cash relative to the M2 monetary measure.

Loan Sharks

The introduction of Hindu-Arabic numerals and advanced mathematical tools to Europe revolutionized commercial bookkeeping and financial calculations. Leonardo of Pisa, known as Fibonacci, introduced decimal systems and computational techniques through his book Liber Abaci, published in 1202. This allowed Europeans to easily calculate interest, currency conversions, and present values.

Fibonacci used practical examples involving everyday commodities like hides, peppers, and cheese to illustrate mathematical applications to lending money. The sequence approaches the golden mean ratio of 1.618.

Religious prohibitions against charging interest created ethical hurdles for Christians, pushing marginalized ethnic minorities into the commercial credit sector. Because the Catholic Church condemned usury and excommunicated lenders, Christians faced severe penalties. Exploiting loopholes, Jewish communities in cities like Venice stepped in to provide credit, often facing social exclusion, residential confinement, and political vulnerability. Venetian authorities confined Jewish moneylenders to a segregated urban area known as the ghetto nuovo, forcing them to wear identifying marks. By 1590, approximately 2,500 Jews lived in Venice.

The Birth of Banking

The Medici family transformed banking from small-scale moneylending into a powerful international enterprise by utilizing scale, diversification, and decentralized partnerships. Rather than operating as a fragile, monolithic firm vulnerable to single defaults, the Medici bank structured its branches as independent partnerships managed by junior partners who shared in profits, spreading risk across currency exchange and trade finance. Giovanni di Bicci de' Medici managed the Roman branch and later expanded into Venice, Rome, Geneva, Pisa, London, and Avignon, eventually becoming the de facto rulers of Florence. The Medici bank held 20,000 florins of capital in 1402 and made 151,820 florins of profits between 1397 and 1420, achieving an annual rate of return of 32 per cent.

The development of central banks and fractional reserve banking enabled the expansion of credit far beyond physical metallic reserves. Institutions pioneered fractional reserve banking by keeping only a fraction of deposits in reserve and lending out the rest. This mechanism allowed for credit creation, changing money from physical metal into bank liabilities.

Key milestones in this evolution include:

• 1609: the Amsterdam Exchange Bank was set up;
• 1656: the foundation year of the Swedish Riksbank;
• 1694: the creation year of the Bank of England.

The Harvard Business School classroom money game simulates how a central bank deposit cascades through multiple commercial banks via reserve ratios to expand the money supply using a typical bank reserve ratio of 10 per cent.

2. Mountains of Debt

Sovereign bond markets evolved from medieval warfare financing and exert immense political power through feedback loops that can make or break governments.

The modern bond market was born out of the financial crises caused by incessant medieval warfare. Faced with crushing deficits from wars, Italian city-states like Florence and Venice forced wealthy citizens to make compulsory loans. They called these loans prestanze or monte, and created secondary markets where these debts could be traded.

Florence used military contractors called condottieri, such as the English mercenary Sir John Hawkwood, to fight its wars. This caused its public debt mountain to soar from 50,000 florins at the start of the fourteenth century to 5 million florins by 1427. Borrowed money accounted for 70 per cent of Florentine revenue in the early fifteenth century.

The Birth of the Bond

Nathan Rothschild built his financial empire by mastering international arbitrage, gold smuggling, and high-stakes bond speculation. During the Napoleonic Wars, the Rothschild network used cross-border family branches to supply gold to British troops.

Nathan Rothschild used couriers and a cross-Channel credit network to move millions in gold coins across blockades to the Duke of Wellington's army. Between 1793 and 1815, the British national debt level reached £745 million. After Napoleon's defeat at Waterloo left the family with excess cash, Nathan Rothschild gambled heavily on British government bonds and made massive profits as prices soared. He sold consols in late 1817, making a profit with a modern value of £600 million.

The Power of the Yield

The bond market exercises immense political power because it acts as a feedback loop that can dictate government policy. When bond markets lose confidence in a government's fiscal health, they sell off holdings and drive up yields.

Bill Clinton's campaign manager James Carville famously stated that he wanted to come back as the bond market because it could intimidate everybody. This increases debt-service costs, widens deficits, triggers further sell-offs, and eventually forces governments to choose between default, spending cuts, or tax hikes. Japan accumulated a mountain of public debt reaching 838 trillion yen, while falling bond prices trigger a 41 basis point jump in mortgage costs.

Hyperinflation and Default

Hyperinflation wipes out government debt by destroying the paper wealth of bondholders and people living on fixed incomes. Following the First World War, heavy reparations burdens, political instability, and massive monetary expansion led to catastrophic hyperinflation in Germany.

The Weimar Republic was saddled with a reparations liability of 132 billion gold marks. During the German hyperinflation of 1923, 20-billion mark notes were in everyday use, and prices soared to an average of 1.26 trillion times their 1913 levels. By the end of 1923, marks in circulation reached 4.97 multiplied by 10 to the 20th power, and peak annual inflation hit 182 billion per cent. This process effectively liquidated the internal debt mountain and devastated the middle-class rentier class through the euthanasia of the rentier.

3. The Evolution of the Company

The joint-stock corporation transformed how you can pool capital and build large enterprises. You can invest in risky long-term ventures while protecting your personal wealth from total ruin.

Joint-stock corporations and stock markets pool capital and drive economic growth, but they are prone to recurring speculative manias and fat-tail crashes.

Joint-Stock Power

The United Dutch Chartered East India Company was formed in 1602 with a novel joint-stock structure. It raised 6.45 million guilders in its initial subscription.

The English East India Company raised 820,000 guilders equivalent capital two years earlier. Joint-stock status means capital is owned collectively by multiple investors. Limited-liability ensures that your risk is restricted solely to the money used to buy your stake.

John Law engineered the first major financial bubble by combining a central bank with a monopoly trading company. He attempted to reflate the French economy by replacing metal coinage with paper banknotes tied to Mississippi Company shares.

The Mississippi Company agreed to lend 1.2 billion livres to pay off the entire French royal debt. The Banque Royale set a floor price of 9,000 livres for Mississippi shares in late 1919.

Bubbles and Panics

Financial bubbles follow a remarkably consistent cycle driven by human psychology and easy credit.

• displacement;
• euphoria or overtrading;
• mania or bubble;
• distress;
• revulsion or discredit.

When the bubble bursts, market participants stampede for the exits.

Blunder-prone monetary policy by the Federal Reserve turned the 1929 stock market crash into the catastrophic global Great Depression. Between 1929 and 1933, approximately 10,000 US banks failed, causing commercial bank deposits to drop by 37 percent and loans by 47 percent. The US stock market declined by 89 percent from 1929 to its nadir in July 1932.

Market Volatility

Stock market price movements do not follow a normal bell curve distribution. They exhibit fat tails, meaning extreme crashes happen much more frequently than standard statistical models predict.

On Black Monday on October 19, 1987, the Dow Jones index fell by 23 percent in a single trading session. Over the past century, 9 stock market plunges of 20 percent or more occurred.

Modern corporate scandals mirror historical speculative manias by relying on aggressive accounting. Enron executives used special-purpose entities to hide massive debts and losses. The company reported 13 billion dollars in long-term debt on audited balance sheets after bankruptcy, while actual long-term debt reached 38 billion dollars. Top executives were paid an average of 5.3 million dollars in its final year of existence.

Over the long run, equities significantly outperform government bonds and bills because shares represent portions of profit-making corporations. An investment of 10,000 dollars in US stocks from 1964 to 2007 with reinvested dividends would have increased by a factor of nearly seventy to yield 700,000 dollars.

4. The Big Uneasy

You constantly struggle against the unpredictability of the future. Humanity historically relies on savings, mutual assistance, or state bailouts when disasters strike.

Insurance and modern welfare systems tame the unpredictability of the future through actuarial mathematics, state mandates, and financial derivatives.

Natural disasters reveal the limitations of private insurance and create heavy reliance on post-disaster government assistance. Hurricane Katrina severely damaged New Orleans in 2005, destroying homes and triggering over 1.75 million property and casualty claims with insurance losses exceeding $41 billion. A total of 1,836 Americans lost their lives as a result of Hurricane Katrina, while the federal government provided $109 billion in post-disaster assistance for 2005 hurricanes.

Mathematical Foundations

Modern insurance is built upon crucial mathematical breakthroughs in probability, life expectancy, and statistics developed between 1660 and 1764. Mathematicians created the theoretical basis for evaluating risk through six breakthroughs:

• Pascal's probability insights;
• Graunt and Halley's life tables;
• Bernoulli's law of large numbers and utility theory;
• de Moivre's normal distribution bell curve;
• Bayes's theorem on inference.

Edmund Halley used birth and death data from the Prussian town of Breslau to calculate the odds of survival at different ages. He analyzed 1,238 recorded births and 1,174 recorded deaths to establish that you faced 100 to 1 odds that a man of 20 dies not in a year, and 38 to 1 for a man of 50.

Two Church of Scotland ministers invented the first true modern insurance fund in 1744. Robert Wallace and Alexander Webster rejected the traditional pay-as-you-go model of charity. They based their Fund for a Provision for the Widows and Children of the Ministers of the Church of Scotland on 930 ministers in life at all times. They projected their fund's capital to grow to 58,348 pounds by 1765. Their mathematical projection was off by only one pound, reaching 58,347 pounds of actual free capital.

From Warfare to Welfare

State-sponsored welfare systems were originally introduced not as socialist or altruistic measures. Conservative politicians sought political loyalty and social stability through these programs. Otto von Bismarck introduced the world's first compulsory state health insurance and old-age pension system in Germany. He argued in 1880 that a man with an old-age pension is much easier to deal with than a man without that prospect.

Japan developed the world's most successful post-war welfare state out of an intense militaristic mobilization during the mid-twentieth century. Between 1938 and 1944, the number of Japanese citizens covered by state health insurance schemes increased nearly a hundred-fold from 500,000 to over 40 million. By 1975, this warfare-welfare state spent 9 per cent of national income on social security.

Chile pioneered the dismantling of the traditional welfare state by replacing public pensions with mandatory private personal retirement accounts. Workers opted out of state systems by putting 10 percent of their wages into private Personal Retirement Accounts managed by competing Administradoras de Fondos de Pensiones. Around 7.7 million Chileans held Personal Retirement Accounts by the end of 2006. This helped achieve a 30 per cent of GDP savings rate by 1989.

Derivatives and Hedging

Financial derivatives and hedging instruments allow corporations and wealthy investors to eliminate price risks. You can utilize futures contracts, call options, put options, swaps, credit default swaps, and weather derivatives to transfer tail risks. Total notional amounts outstanding of over-the-counter derivative contracts reached $596 trillion in December 2007. They carried a gross market value of $14.5 trillion.

5. The Property-owning Aristocracy

Historical aristocratic fortunes collapsed not because land lacked value. Magnates over-leveraged their estates with high-interest debt while agricultural incomes fell. Nineteenth-century British landowners borrowed heavily to fund opulent lifestyles and estate improvements. They assumed land was risk-free because it is immobile. However, the repeal of the Corn Laws and plunging global grain prices destroyed agricultural returns. Heavily indebted aristocrats faced financial ruin.

Richard Plantagenet, 2nd Duke of Buckingham, accumulated over a million pounds in debt. He was forced to auction off the entire contents of Stowe House in 1848. His gross annual income in 1845 was £72,000, yet his accumulated debts reached £1,027,282. Total proceeds from the 1848 auction at Stowe House amounted to just £75,000.

Real estate and mortgage markets provide the foundation for household wealth and capitalist stability, but deregulation and securitization can trigger systemic meltdowns.

Rise of Homeownership

The US government rescued the collapsing housing market during the Great Depression by standardizing long-term, amortized mortgages and providing federal deposit insurance. Prior to the 1930s, American mortgages were short-term, non-amortized balloon loans that failed when the Depression struck. There were 500,000 foreclosures in the US in 1932 and 1933.

The New Deal introduced institutions like the Home Owners' Loan Corporation and the FHA to back long-term loans. These bodies established secondary markets through Fannie Mae and protected savings in local thrifts. Frank Capra's movie It's a Wonderful Life depicts the vital social role of local Savings and Loan associations in helping working-class families escape slums.

Federal housing policies and credit rating systems institutionalized racial segregation and denied minorities equal access to homeownership. Federal Home Loan Bank Board maps marked predominantly Black neighborhoods in red, a practice known as red-lining. This subjected minority borrowers to higher interest rates or outright denial of federally backed loans.

A real estate developer in Detroit built a six-foot-high wall across the 8 Mile district in 1941 to separate white and Black neighborhoods. This ensured the white side could qualify for FHA loans. One in five Black mortgage-borrowers paid an 8 percent rate in the 1950s compared to under 7 percent for whites. Racial red-lining remained active until it became a federal offense in 1968.

Margaret Thatcher dramatically expanded British homeownership by selling off public council houses at a discount and introducing mortgage interest relief. To build a conservative political constituency among the working class, her government allowed millions of council tenants to buy their homes at bargain prices. The share of British owner-occupiers rose from 54 percent in 1981 to 67 percent ten years later in 1991.

The S&L Scandal

Deregulation of Savings and Loan associations in the 1980s combined with government-insured deposits to create a massive moral hazard and a historic financial fraud scandal. When high inflation and interest rates hammered traditional S&Ls, deregulation allowed them to pay unlimited deposit rates and invest in high-risk projects. The government insured deposits up to $100,000, which triggered widespread looting and fraudulent real estate flips.

Dallas developer Danny Faulkner used brokered deposits from Empire Savings and Loan to fund speculative condo projects along Interstate 30. He bought land cheaply and flipped it to affiliated buyers at massively inflated prices. The total final cost of the S&L crisis between 1986 and 1995 reached $153 billion. Taxpayers paid $124 billion of that total.

Securitization and Subprime

The invention of mortgage-backed securities transformed Wall Street by converting illiquid home loans into tradable bonds distributed globally. In June 1983, Salomon Brothers trader Lewis Ranieri pioneered issuing the first collateralized mortgage obligation by bundling thousands of individual mortgages. Securitization grew from 10 percent of the home mortgage market in 1980 to 56 percent by 2007.

This process divorced the original borrower from the ultimate investor, spreading mortgage risk worldwide but obscuring underlying credit quality. Norwegian municipalities invested millions of taxpayers' dollars in complex collateralized debt obligations secured by American subprime mortgages without understanding the underlying risks.

The subprime mortgage boom relied on risky adjustable-rate loans to low-income borrowers. This triggered widespread foreclosures and a global financial panic when interest rates rose. Lenders targeted vulnerable urban neighborhoods with teaser-rate, interest-only, and 100 percent LTV loans. When the Federal Reserve raised short-term interest rates from 1 percent to 5.25 percent, monthly payments reset higher.

On a Memphis courthouse step, the author witnessed over fifty homes sold off in a single afternoon due to mortgage foreclosures driven by subprime defaults. By May 2008, there were 1.8 million mortgages in default. This resulted in $318 billion in bank write-downs.

Microfinance demonstrates that poor entrepreneurs, particularly women without real estate collateral, can be exceptionally reliable credit risks when organized into mutual support groups. Because traditional property titling often fails to unlock credit for the very poor, microfinance institutions issue tiny loans directly to women. In 1983, Muhammad Yunus founded the Grameen Bank, where women formed weekly accountability groups to manage typical starting loans of $200.

Betty Flores used small loans from the microfinance organization Pro Mujer to expand her coffee stall in El Alto, Bolivia, and fund her daughters' schooling. These programs prove that women manage capital effectively. They maintain significantly lower default rates than men.

6. Globalization and Armageddon

The great divergence in living standards between East and West from 1700 to 1950 was driven partly by institutional and financial shortcomings in China. Unlike Renaissance Europe, China's unitary empire lacked fiscal competition to drive financial innovation. It easily financed deficits by printing money, reducing the incentives to develop commercial bills, bonds, and capital markets. In 2006, the ratio of US to Chinese per capita income stood at 22.9 to 1. Over the past thirty years, China has experienced an 8.4 per cent compound annual growth rate of per capita GDP.

Imperial Finance

In the first era of globalization, British imperial power acted as an effective enforcement mechanism that reduced default risk for overseas investors. By imposing British property rights, the rule of law, and administrative control over colonies and informal spheres of influence, the British Empire made debt contracts enforceable and lowered yields on colonial bonds.

William Jardine and James Matheson lobbied Lord Palmerston for military intervention during the Opium War. This led to the acquisition of Hong Kong and the establishment of treaty ports with extraterritorial immunity. Chinese authorities surrendered and destroyed opium valued at £2 million in 1839. Between 1865 and 1914, British investors put £74 million into Chinese securities.

The Return of Globalization

The first age of globalization ended abruptly in 1914 because economic integration and rising migration generated a nationalist and agrarian backlash culminating in war. Rising tariffs and immigration restrictions in the decade before 1914 reflected resistance from Europe's agrarian elites against agricultural price declines and emigration. This ultimately led to a catastrophic collapse of international credit. By 1910, 14 per cent of the US population was foreign born.

The assassination of Archduke Franz Ferdinand by Gavrilo Princip on June 28, 1914, triggered a liquidity panic, the failure of bill brokers and jobbers, and the closure of world stock markets for up to five months.

Chimerica and Modern Crises

International trade and capital flows generate massive prosperity and financial symbiosis, but they also carry the seeds of geopolitical backlash and systemic crises.

Chimerica represents a symbiotic economic union where Chinese savings and cheap labor funded American consumption and kept global interest rates low. China maintained currency pegs by buying US government debt with its current account surpluses. This enabled Americans to borrow heavily and drove a massive post-2000 expansion in global financial instruments. In 2007, China ran a current account surplus of $262 billion while the United States needed to borrow $800 billion from the rest of the world.

7. The Descent of Money

Financial history operates through institutional mutation and natural selection rather than linear growth. Just like biological organisms, financial institutions undergo mutation through innovation and face extinction if they underperform. Market selection acts as the main driver, allowing institutions with successful traits to proliferate.

Financial history can be best understood as an evolutionary process driven by institutional mutation, natural selection, and creative destruction rather than mere corporate growth.

Between 1989 and 1997, an average of 611,000 businesses vanished each year out of a total of 5.73 million firms in the United States. This represents an average annual extinction rate of 10 per cent for US companies.

Financial instability is fundamentally caused by true uncertainty about the future. This condition is distinct from measurable risk and cannot be calculated scientifically. Unlike games of chance such as roulette, where probabilities are known, many economic events are entirely unique.

Human beings exhibit systematic cognitive biases and heuristic errors. These flaws make you deviate from the rational actor model assumed by neoclassical economics. Psychological experiments show that individuals display asymmetric risk aversion, fearing losses significantly more than they value equivalent gains.

Daniel Kahneman and Amos Tversky gave subjects 1,000 Israeli pounds and offered choices between gambles and certain payouts. When framed as losses instead of gains, the majority shifted from risk aversion to risk-seeking behavior for identical payoffs. Specifically, 84 per cent chose the certain 500 pound gain over a 50 per cent chance of 1,000 pounds. In contrast, 69 per cent chose the 50 per cent chance of losing 1,000 pounds over a certain 500 pound loss.

Modern financial crises generate massive write-downs and liquidity strains that threaten the balance sheets of major banking institutions. Losses on asset-backed securities force financial institutions to raise fresh capital and shrink their balance sheets. When off-balance-sheet shadow banking entities collapse, credit contraction becomes severely constrained.

In the wake of the 2007 credit crunch, approximately $318 billion of write-downs were acknowledged by May 2008 out of an estimated total exceeding $1 trillion. Financial institutions also raised $225 billion of new capital during this period. State intervention and implicit bailout guarantees create moral hazard by protecting inefficient institutions, which ultimately thwarts the natural evolutionary process of the market. Regulators often intervene to prevent the collapse of institutions deemed too big to fail. Japan's economic stagnation in the 1990s served as a warning against propping up underperforming banking sectors and failing to write off bad debts.

1. Recognize that money is fundamentally a matter of trust and confidence rather than intrinsic physical value, making inflation a permanent hazard when states abuse their power to issue currency.
2. Treat excessive debt as a heavy operational burden that creates dangerous feedback loops for governments, corporations, and your personal household finances alike.
3. Embrace the power of joint-stock ownership for long-term capital accumulation while remaining deeply suspicious of sudden speculative manias and asset bubbles.
4. Protect your future against unforeseen disasters through robust insurance mechanisms and prudent risk management strategies rather than assuming favorable trends will continue indefinitely.
5. View real estate and mortgage markets as foundational tools for wealth building that require careful leverage discipline to avoid catastrophic personal insolvency during systemic downturns.
6. Acknowledge that global financial interconnectedness generates immense prosperity alongside deep vulnerabilities, requiring you to diversify your assets against geopolitical and macroeconomic shocks.
7. Accept that financial crises are an inevitable feature of evolutionary market selection rather than temporary aberrations, and maintain sufficient liquidity to survive fat-tail market crashes.

10 Key Ideas

1. Money is essentially trust inscribed on various mediums rather than physical metal, and excessive extraction of precious metals triggers destructive resource curses.
2. Sovereign bond markets evolved from medieval warfare financing and exert immense political power through feedback loops that can make or break governments.
3. Joint-stock corporations and stock markets pool capital and drive economic growth, but they are prone to recurring speculative manias and fat-tail crashes.
4. Insurance and modern welfare systems tame the unpredictability of the future through actuarial mathematics, state mandates, and financial derivatives.
5. Real estate and mortgage markets provide the foundation for household wealth and capitalist stability, but deregulation and securitization can trigger systemic meltdowns.
6. International trade and capital flows generate massive prosperity and financial symbiosis, but they also carry the seeds of geopolitical backlash and systemic crises.
7. Financial history can be best understood as an evolutionary process driven by institutional mutation, natural selection, and creative destruction rather than mere corporate growth.
8. Human beings exhibit systematic cognitive biases and heuristic errors that make them deviate from the rational actor model assumed by neoclassical economics.
9. State intervention and implicit bailout guarantees create moral hazard by protecting inefficient institutions, which ultimately thwarts the natural evolutionary process of the market.
10. Widespread financial illiteracy leaves individuals vulnerable to debt traps and economic shocks, making it essential to understand money as a complex evolutionary technology.