The Agta Negrito people have been hunters and gatherers in the tropical rain forests of the Philippines for centuries. This book investigates a small group of the Agta living on Luzon Island during their transition from a foraging society to a landless group of agricultural workers.

The core of the book is a demographic study of fertility, mortality, and migration over a 44-year period. It is one of only two studies that have completely reconstructed the population dynamics of a foraging group without relying on mathematical models. Ethnographic and narrative historical sections of the book establish the contexts for the demographic data and enhance the study's readability.

As a case history of social and population dynamics in a remote frontier region, the work describes the impact of international commercial interests on both the rain forest and the landless peasantry seeking to survive.