Check out this book on Goodreads: The River of Doubt: Theodore Roosevelt's Darkest Journey http://www.goodreads.com/book/show/78508.The_River_of_Doubt This book is less about doubt than it is about the journey through doubt to discovery: the discovery of true character through grit and determination. Read it if you dare to wander with the iconic personality of Roosevelt on his journey through the unexplored world of the Amazon rainforest.