A science fiction classic. Haldeman's book chronicles a war between humankind and a race of aliens. Haldeman stays true to modern physics: since warriors must travel great distances (with the help of relativistic worm hole trickery), they age only a few years while hundreds of years elapse back on earth. Thus, soldiers find themselves returning from battle to earth generations after their families have passed away, and political changes have rendered their reasons for fighting moot. A tremendous story and very satisfying to the scientifically minded.