The River of Doubt: Theodore Roosevelt's Darkest Journey.
(Book)

In a gripping account, Millard focuses on an episode in Teddy Roosevelt's search for adventure that nearly came to a disastrous end. A year after Roosevelt lost a third-party bid for the White House in 1912, he decided to chase away his blues by accepting an invitation for a South American trip that quickly evolved into an ill-prepared journey down an unexplored tributary of the Amazon known as the River of Doubt. The small group, including T.R.'s son Kermit, was hampered by the failure to pack enough supplies and the absence of canoes sturdy enough for the river's rapids.