La Guerre éternelle, suivi de Libre à jamais

A man is drafted into the space army and shipped around the galaxy fighting for galactic supremacy. He doesn't exactly love the war, but he doesn't seem to have many particularly strong opinions about most things. Pitched to me as the anti-war antidote to Starship Troopers, the main thing I took away was that Starship Troopers wasn't exactly pro-war either, only the protagonist was. Still, it was interesting to read both!

An allegory for the Vietnam war via alien encounters and the human consequences of near-light travel that tells more about the concerns of the seventies than about the future. It's a good piece of scifi but it's dated, and should be read, I think, as a historical document. Otherwise you'll get really annoyed about the homophobia implied in the future of mandatory homosexuality.