You won't be scolded when browsing the stacks at Subterranean Books; no one will spy to make sure you pull the book off the shelf the "right" way, nor will they give you a sideways glance if your purchase is "lowbrow" or "popular." They're nice people who obviously love the "previously owned and read" books they sell and assume that you love books just as much. In less than a year, Subterranean Books, which lives in the space once occupied by the far snootier A Collector's Books, has created a store with more depth and intelligence than other used -- and most new -- bookstores in town. Their fiction section is rich with both the college prerequisites and, best, a great modern selection; they've got a fantastic African- American-studies section, an equally deep gay-studies section, an unparalleled music- and film-criticism section, art books out the wazoo and a range of cookbooks. Oh, and a selection, though tiny, devoted to alchemy and black magic, and another consisting of erotica -- all the stuff your preacher and parents warned you about. In the past few months we've bought first-edition David Foster Wallace stories; Nick Tosches' great bio of Jerry Lee Lewis; Nan Goldin's amazing book of transvestites photos, The Other Side; Mark Helprin's Memoir From Antproof Case; and a first-edition Pynchon novel. These fine books are all housed in an atmosphere perfect for relaxation and browsing: Inevitably, classic jazz or soul is ringing from the speakers, and the owners greet you with a sincere smile and offer their opinions, if asked. The Loop has always needed a great used bookstore; it's finally got one.