Tina Quark has enlisted the help of her brother, Kevin, and Giles Barnes to locate some books for her at the library for her latest invention. Of course, they end up in the basement in a dusty old room, where no one would ever want to read these ancient tomes. While searching Giles sees books floating and Tina checks her trusty ghostometer but does not get a single ghostly reading. If not a ghost, then why are magic books floating? "It's just me" replies a voice and Barnes & The Brains now match science and wit to figure out how to help poor Mr. Kapoor, beginner magician who made himself invisible and can't reverse the spell. Totally independent from the first book, though it does briefly mention events from that book. This book also gives a quick rundown on the characters and their status for those who haven't read the first book. I really enjoyed this one, even more than book 1 (Ghosts). The introduction of the bored librarian who was excited to help them in any small capacity was funny and she had some giggle inducing lines. I'm attached to the characters and I can see some growth in their relationship. Another well-written, unique plot and highly recommended first chapter book from Oppel. I look forward to reading book 3.