I, Robot by Isaac AsimovFoundation by Isaac AsimovHyperion by Dan SimmonsThe Man in the High Castle by Philip K. DickThe Fall of Hyperion by Dan Simmons
Science Fiction Hall of Fame
42 books — 7 voters
The Martian by Andy WeirThe Forever War by Joe HaldemanLeviathan Wakes by James S.A. Corey
Hard SF reading group
86 books — 58 voters

Old Man's War by John ScalziStarship Troopers by Robert A. HeinleinEnder’s Game by Orson Scott CardThe Forever War by Joe HaldemanHyperion by Dan Simmons
Space Opera & Military SF
475 books — 285 voters