Books for Soldiers?

Does anybody here know anything about an organization called Books for Soldiers? According to their website, they collect (surprise!) books to send to members of the armed forces. Seems like a good idea, but I never heard of it before.

Especially any service members, their friends or family: What do you think of this concept? Do you think this is worthwhile?

Also, of the various other support organizations, which do you think the actual folks on the front lines appreciate most: The USO? Groups like the Navy-Marine Relief Society? Or what? For those of us who don’t have personal friends or family members in the military, but who appreciate the sacrifices they make, what is the best way, in addition to paying our taxes (!) that we can make a difference to them and show our appreciation?