1914. Brazil’s Rio da Dúvida, the River of Doubt. Plagued by hunger and suffering the lingering effects of malaria, Theodore Roosevelt, his son Kermit, and the other members of the now-ravaged Roosevelt-Rondon scientific expedition are traveling deeper and deeper into the jungle. When Kermit and Teddy are kidnapped by a never-before-seen Amazonian tribe, the great hunters are asked one thing in exchange for their freedom: find and kill a beast that leaves no tracks and that no member of the tribe has ever seen. But what are the origins of this beast, and how do they escape its brutal wrath?

Roosevelt's Beast is a story of the impossible things that become possible when civilization is miles away, when the mind plays tricks on itself, and when old family secrets refuse to stay buried. With his characteristically rich storytelling and a touch of old-fashioned horror, the bestselling and critically acclaimed Louis Bayard turns the story of the well-known Roosevelt-Rondon expedition on its head and dares to ask: Are the beasts among us more frightening than the beasts within?