The rest of what you shell out for, say, the new Donna Tartt novel pays for the publisher's overhead (the cost of maintaining a staff of editors, proofreaders, book designers, publicists, sales representatives and so on), and for the cuts taken by distributors (who run warehouses that supply books to retailers) and booksellers. Promoting the book is another expense: printing up catalogs presenting each season's titles to booksellers and the media, purchasing ads, mailing out hundreds of review copies to critics and sending the author (if he or she is lucky) on a book tour. So are shipping fees and the storage costs on unsold copies.