Bolerium Books is the wiser older sister of some other, more irritating radical bookstores we could name. You won't stumble into Bolerium on your way to the touristy head shop, for example. In fact, you might miss it altogether. It's up three flights of narrow stairs above a paint shop, and you have to buzz to get in. (Hint: Say something intelligent into the intercom, like "Uh, bookstore?") Once you find it, though, you're in a nerdy left-wing page-turner's paradise. S.F. Communist detective fiction writer Mike Quinn, 1930s pen name Robert Finnegan? You'll find him here. "Father of the beatniks" Kenneth Rexroth's novels? Bolerium usually stocks them. Ask for San Francisco history, and the sardonic but friendly people who work there may show you across the hall to another room holding soaring shelves of rare finds. Far from a flashy shock shop, Bolerium is a place to think and read: It's very San Francisco that way.