Mr. Penumbra's 24-Hour Bookstore was fun and quirky. It's got books, tech, typography, old-fashioned quests, a mystery, and a secret society. It's a book about the intersection of old and new, about friendship, and about the meaning of life. The book has twists and turns, and perhaps a little too much Google, but Sloan's easy and straightforward writing style keeps things moving, and the interesting characters keep you turning the pages.
Bottom line: a fun read