Two Favorite Books for Boys

I read many wonderful books as a boy, but there are two adventure stories that I still enjoy reading as an adult:

My Side of the Mountain (by Jean George) -- the story of a boy set off to live in a tree by himself in the Catskills, and his adventures there. 

Banner in the Sky (by James Ramsey Ullman) -- the story of a boy who dreamed of climbing The Citadel, the last great unclimbed mountain in the Alps. 

Recommended for your boys!  (Note: Both have been made into movies, but the books are better.)

What other books for boys do you recommend?