@abge: "I was shocked when I learned how many movies were based on his stories. "
Every decent scifi from 1970-2000... I'd say 60-80% were Dick or, as they say, "Philip K Dickian" movies. Seriously. He has an adjective name... including the middle initial. That's awesome!
Warning on the Forever War saga. I read Forever Peace which was good, but the end? It's like Haldeman decided he wrote enough and ends the book in 12 pages. That it is really bad. Really, really bad. In face, I'm going to spoil it for you so you don't waste your time reading it:
They keep undergoing weird crap happening to them, then all humanity except those on the ship vanish, so they decide to point in a direction, turn on their fastest FTL drive, and not stop. Eventually the ship stops completely, they meet 'God' who basically says they are trying to travel beyond the playground he created, hid all the humans in the grand canyon (seriously, Haldeman?), and then warps them home without a ship. Later on they find out that God changed Plank's constant and some general prove theories of quantum mechanics, so it'll be decades, possibly centuries before they'll be able to travel the stars again. The end. *facepalm*