I owned multiple Microprose games and the manuals that came with the games were simply fantastic.

There would be a section on the gameplay itself and then usually some historical reference about the setting of the game. E.g. if it was a WW1 flight combat simulator, there would be a section on the history of aerial dogfighting and then specs on each plane.

I know that nowadays it's common knowledge that most people don't read the manuals and it's easier to get people into a game with a combination first level /introduction/tutorial. That being said, I feel like we lost something by taking out the manuals with all that rich historical detail.