I borrowed this sci-fi classic. It is excellent. The premise is simple - a man is conscripted to fight against a poorly-understood alien menace, but due to relativity he comes back to a completely changed world after each short tour of duty. It's a simple concept for an anti-war book by a Vietnam vet, but it's superbly crafted. I haven't read Heinlein's Starship Troopers (the thought fills me with dread after the last Heinlein I read), but between the film and what I've heard, it's not hard to see this is a fine, twisted parody, as well as great book in its own right.