The narrator recounts riverine and overland journeys from the Amazon estuary into the tropical interior, following tributaries and remote landscapes. He documents encounters with numerous indigenous communities, detailing their material culture, social organization and ritual practices, including headhunting and other striking ceremonies. Ethnographic observation is blended with natural-history notes and travel anecdotes, and the volume is illustrated with numerous sketches, photographs and maps. Chapters move between first contacts, the discovery of little-known groups, descriptions of archaeological features such as a rock temple, and reflections on navigation and survival in dense rainforest.