From the outside, Riverwalk Books in Chelan, Washington, appears to sell books in its 1,500-square-foot space. And, of course, it does. But a number of other activities take place in the nine-year-old store as well, thanks to the creativity of owner and founder Libby Manthey. She took seriously the lessons she learned at ABA's prospective booksellers school over a decade ago, and more recently at the education sessions given at PNBA meetings. "I know that I have to keep my eye on the bottom line -- always on the bottom line.