The work opens with an introduction to the geographical setting of the Abra province, detailing the rugged mountain ranges, river systems, and climate that have historically isolated the Tinguian in small, self-sustaining communities. The author evaluates previous theories regarding the racial origins of the tribe, comparing physical measurements of the Tinguian, Ilocano, Apayao, and Bontoc Igorot with southern Chinese and Malay populations to establish their true ethnic affinities.
A substantial portion of the text is dedicated to the lifecycle, beginning with birth practices, pregnancy taboos, naming customs, and childhood socialization. Marriage customs are examined from the initial betrothal negotiations and bride-price agreements to the wedding ceremonies, post-marital observances, and grounds for divorce.
The volume provides extensive documentation of funeral rites, mourning restrictions, burial types, and beliefs concerning the afterlife and the spirit world. The author categorizes natural spirits and ancestral shades, detailing the role of mediums, the mechanics of trance possession, and the execution of magical acts and omens used to foretell future events.
A comprehensive classification of ceremonial structures—such as the balaua, kalangan, and pala-an—and ritual paraphernalia is provided to illuminate the complex religious practices of the tribe. The narrative details minor ceremonies like the dawak, pinaing, and bawī, alongside major rituals including the pala-an, tangpap, kalangan, and the seventeen-day sayang ceremony.
Finally, the text examines social organization, village governance under the leadership of the elders, and traditional economic pursuits. These include wet-rice terracing, agriculture, weaving, pottery, iron-working, basketry, and personal adornment, concluding with an analysis of music and decorative arts.
