This book is the journal of a study trip that Carlos S Carbonell made with five other men in 1948. They travelled through Argentina, Bolivia and Peru to Lima, and from there to Pucallpa on the Ucayali River. There they boarded the small launch of a trader and went to Iquitos. From Iquitos, by various means of river conveyances, reached Manaos and Belem, from where they returned to Montevideo. This journal registers the incidents of the trip and describes the places they travelled through, giving a candid picture of a part of the world that has remained for many years, almost unchanged.