People come to 25th Street in search of St. Thomas Aquinas, Julia Child, Mark Twain and A. Aubrey Bodine. "The Book Block," as it's informally called, has emerged as Baltimore's literary rialto. The section of 25th between Charles Street and Maryland Avenue now has four thriving shops where customers spend long Saturday afternoons perusing volumes they may or may not buy. "It's the burgeoning of a nice little book community," said Teresa Johanson, of the Kelmscott Book Shop. She and her husband, Donald, who once both taught in colleges, were the first to locate on the street some 14 years ago. "Our mainstay is literature. There are plenty of people who can't afford a first edition of Mark Twain, but who will pay $25 for a nice 19th century edition," she said. On a recent afternoon, a recorded Smetana tone poem filled her spotlessly clean, well-organized shop. She and her husband have two floors in two side-by-side rowhouses. Over the years, the Johansons have established themselves as the city's premier quality sellers of rare and used books. You don't come here to buy "Scarlett." But if you are after a book of Roman Catholic Lenten devotions published in Baltimore in 1850, this is the right address. So rare, in fact, was some of the Kelmscott inventory that it appealed to the burglars who made off with $40,000 worth of books in August. Many of the more unusual volumes bore the bookplate of the late Johns Hopkins professor Don Cameron Allen. Just down the street, the radio at the Tiber Book Shop is tuned into rock oldies on WQSR. A Park School student and his girlfriend pop in the door. They're looking for a book of Carl Jung. Elissa Bellassai sits behind the counter. She knits a lavender baby blanket and dispenses all sorts of advice and observations. "We're a very laid back kind of place," she said. "We get everybody in here. There are literate street people who come in to buy a book for a $1. When we had the math convention, the store was loaded with people. Some will tear out a sheet from the Yellow Pages." Whit Drain, a former Baltimore city planner, opened Tiber Books with former Hutzler's buyer Bob Kotansky. Their first effort was in Ellicott City where they picked up the name from Tiber Creek, a tributary of the Patapsco River. "We learned a lot about retailing in Ellicott City. You have to have a big building and stock a wide assortment of books. You'd be visited by zealous specialists there, but there also just wasn't the breadth of customer on 25th Street," Drain said. His shop now holds about 75,000 titles. "The only reason I opened here was the presence of the other shops," said Ken Rosenberg, whose Book Miser opened on 25th Street last year. Cheap rent and lots of space are prerequisites for a successful bookstore, Rosenberg said. "I'm of the school of thought that books should not be in heaps, dark and crowded," he said, explaining the need for space. Low rent is essential because "books don't sell that quickly." The 25th Street book shop owners say that some of their trade comes from Washington and Montgomery County, where high retail rents have squeezed out some book sellers. They say the Washingtonians enjoy a Saturday's shopping in Baltimore, perhaps coupled with a visit to a local museum or a restaurant. The presence of other used bookstores in nearby Waverly also helps business. "It would be nice if the city put up a sign that said 'Book Row' or something. After all, this is supposed to be the city that reads," said the Kelmscott's Teresa Johanson. As to the future of her business, she's optimistic: "I feel there's a re-evaluation of people's values and ideals. It will lead them back to books. I can't keep a copy of Thoreau on the shelves. Maybe the 1960s are returning."