The “hard” sci fi trio: Haldeman (Forever War and Forever Peace), Heinlein (Starship Troopers), and Drake (Hammers Slammers).
From a purely narrative perspective, Dan Abnet’s Eisenhorn, Ravenor and Pariah. I find myself torn between hard and soft sci fi when it comes to wargaming. On one hand, I love the sheer opportunity soft/Gothic sci fi offers; daemons, Necrontyr, acro-flagellants, religious zealotry, et cetera. On the other hand, I really want the basics of the game to work as according to some semblance of logic; bullets hurt, heavy weapons tend to hurt all the more, troops to not stand by gormlessly while being charged by foot infantry, etc.
That said, I really want a game some time that isn’t 40K. Because the 40K rules actually hurt my brain to play.
The Nefarious Fu Manchu....In SPAAAACE