The Once and Future King
T.S. White
Captains Courageous, Kim, The Light that Died
Rudyard Kipling (In fact, anything by Kipling)
The Honor Harrington series (Horatio Hornblower IN SPAAACE!!!!) Honor, duty, courage in a Royal Navy in the far future with good hard science mixed in. The Hero (heroine?) is female, and a great positive role model.
David Weber
The Hyperion series (Lots of philosophical insights but may be too advanced.)
Dan Simmons
I appreciate the suggestions. Thanks.
Some of the Honor Harrington books might be just a touch racy for a 12-13 y/o, but would be approriate in a few years. Good reading.