The name of this book is secret (Secret series #1)

Warning: this description has not been authorized by Pseudonymous Bosch. As much as he'd love to sing the praises of his book (he is very vain), he wouldn't want you to hear about his brave 11-year old heroes, Cass and Max-Ernest. Or about how a mysterious box of vials, the Symphony of Smells, sends them on the trail of a magician who has vanished under strange (and stinky) circumstances. And he certainly wouldn't want you to know about the hair-raising adventures that follow and the nefarious villains they face. You see, not only is the name of this book secret, the story inside is, too. For it concerns a secret. A Big Secret. Cass sees potential disaster everywhere, so that's why no one believes her when a classmate is kidnapped by Dr L and Ms Mauvais. No one except for misfit Max-Ernest. So they team up in order to solve the mystery of the magician's notebook and the Symphony of Smells, to discover a secret that's been lost to the ages, and then finally to rescue their classmate before his brain is sucked out through a straw. Along the way there are puzzles to solve and word games to play and also they will face incredible danger This is the story of a secret. A secret so big and dangerous that even the story itself is a secret. To find out what it is, you have to risk everything... Self-described survivalist Cass sees potential disaster everywhere, so no one believes her when a classmate is kidnapped by the dazzling but dangerous Dr L and Ms Mauvais. Two eleven year olds try to solve the mystery of a dead magician and stop the evil Dr. L and Ms. Mauvais, who are searching for the secret of immortality First published: New York : Little, Brown, 2007. For primary school age. Series The secret series -- 1