This book is designed for the Role Player with a historic Horror bent, specifically for "Call of Cthulhu" but can be read by anyone. The bulk of the book is made up of the entire text of "Through the Brazilian Wilderness" written by President Theodore Roosevelt. His writing describes a journey taken by himself and acquaintances in 1913, through the steamy jungles of Brazil travelling down the uncharted River of Doubt. This was no pleasure cruise. This journey was an exploring adventure of toil, fear, danger and murder. The jungle that surrounded them for months contained dangerous animals and threatening indigenous people, the water even held man eating fish. Footnotes appear throughout detailing elements and suggestions for turning this epic journey into a Role Playing campaign. An appendix at the end suggests some character profiles for the main protagonists. The Roosevelt-Rondon expedition is the perfect historical source for a role playing campaign.