Robin Sloan’s Mr. Penumbra’s 24-Hour Bookstore is a nerdy dude’s ode to everything nerdy dudes love: technology, coding, tabletop RPGs, startup culture, smart people, boobs (not a typo), books, typefaces, and everything else in that vein, including the dorky guys that get the beautiful girls. It’s set in San Francisco, in an old-school bookstore with …