I currently work with a 23 year old police cadet who is new to firearms. Since the department issues Glock 21's, he bought himself one. He is constantly peppering me with questions ("Why is a .45 better than a 9MM?", "Why would anyone want a revolver?" etc;), and comes up with pictures or internet articles about every "black gun" ever made or even conceived of. I was thinking of finding a down to earth, common sense, gun book as a gift. Or possibly something else?

Any suggestions gents?