The one time I found I really needed to get players into the groove for anything I ran was Shadowrun when few if any of the players had read anything even vaguely cyberpunk-ish. To remedy that, I handed around the first accompanying volume of fiction, the Into the Shadows braided anthology, for them to read in advance of the character generation session. In other cases, my players seem to have already had some idea of the genre or at least conventions typical of these games absorbed by osmosis from the surrounding culture. The main exception I recall was a player who just wasn't into superheroes who joined in one session of Champions. I don't think a reading assignment would have helped in the short time available.
The time I really went looking for genre material (as opposed to things like historical references for period context before finally not getting around to joining the Saxum Caribetum saga) was when running Vampire — and there it was easy enough to find source material in the usual bookshops — which I then plundered for NPCs.