From our collecting books for troops, don't send:

*pictures of nude men or women, or sexually explicit materials.
*quantities of materials critical of Islam (personal use is okay).

Authors and book types that the troops like are almost any fiction, especially action stuff like Tom Clancy but almost anything, really; almost all nonfiction, including poetry; outdoor-type magazines (Outdoor Life, etc.). Don't send hardbacks, as they are simply too much weight and you can't easily carry them around -- paperbacks in good condition. There are plenty of Bibles, Books of Mormon, and so on. Science fiction and fantasy are good -- basically 'most anything to give the mind a vacation.

Remember that the military will almost certainly vette this before it is released.