National Bestseller At once an incredible adventure narrative and a penetrating biographical portraitthe bestselling author of Destiny of the Republic brings us the true story of Theodore Roosevelt's harrowing exploration of one of the most dangerous rivers on earth. The River of Doubtit is a black, uncharted tributary of the Amazon that snakes through one of the most treacherous jungles in the world. Indians armed with poison-tipped arrows haunt its shadows; piranhas glide through its waters; boulder-strewn rapids turn the river into a roiling cauldron. After his humiliating election defeat in 1912, Roosevelt set his sights on the most punishing physical challenge he could find, the first descent of an unmapped, rapids-choked tributary of the Amazon. Together with his son Kermit and Brazil's most famous explorer, Candido Mariano da Silva Rondon, Roosevelt accomplished a feat so great that many at the time refused to believe it. In the process, he changed the map of the western hemisphere forever. Along the way, Roosevelt and his men faced an unbelievable series of hardships, losing their canoes and supplies to punishing whitewater rapids, and enduring starvation, Indian attack, disease, drowning, and a murder within their own ranks. Three men died, and Roosevelt was brought to the brink of suicide.