So it turns out that this novel has almost exactly the same plot as Haldeman's The Accidental Time Machine, except it works much better (this one won the Hugo). It's a much tighter story arc (and more plausible from my limited physics background). It tells the story of Private William Mandella, a conscript in the war against the Taurans. The war takes place deep in space, and the relativistic travel speeds cause time-dilation for the soldiers. When they return home, they have aged little, but most of the people they knew have grown old and died. Each time Mandella returns from the front, Earth society has changed tremendously.

Like each of the other Haldeman novels I've read, this one becomes a love story, but here the ending is "believable" as a consequence of the story and feels more satisfying.

My sci-fi reading background is haphazard and skews pretty far away from space opera, but I'm interested in going back and reading some of the other Hugo and Nebula award winners that are regarded as classics. I think Starship Troopers will be next.