You know you're in a great used bookstore when you go in looking for, say, a dictionary, and come out a few hours later with a book on quantum mechanics, a Norwegian thesaurus, the collected letters of Edith Wharton, a guide to Minnesota's wildflowers, and some classic Spider-Man comics. Midway Books is designed for just this kind of adventurous browsing. The store's three floors--hardcover nonfiction on the first, fiction on the second, and a warren of half-priced paperbacks in the basement--are laid out like a labyrinth, with the full expectation that browsers will get lost in its cozy alcoves. Compared with more refined booksellers like Uptown Minneapolis's Magers & Quinn, Midway's catch-as-catch-can cataloging system can sometimes seem incomprehensible. But the real pleasure here is in the search; Midway, with its tattered charm and vast selection, leaves us consistently overwhelmed, and happily so.