Hidden within Frat Row (or one of many on Penn's campus) is this quaint little two story building converted into a local bookstore. The store itself caters to many classes at Penn but is in itself a treat for anyone looking for a rare book find. The bookstore carries many hard to find books and the service is amazing. The people are very knowledgeable and the books are priced just right (and certainly cheaper than the giant mass-marketed Penn Bookstore).
Go there for your liberal art classes textbooks and, if for nothing else, to say hi to the owners who are always there ready with information, new book releases and, of course, a smile. Don't go there, however, expecting to find EVERY book published, a gigantic selection or anything else but books. The house can get crammed at the beginning of the semester (as the hallways are very tight) and the textbook selection can often overpower the "just to read for fun" selection. Still, visit this gem on campus while its still around and support the local mom-and-pop shops in the area.