The book you see here is the ultimate source of all Cahill knowledge. It contains every buried secret, Cahill weapon or gadget, all the strongholds, and each agent and founder. In it, you will discover the true story of Madeleine Cahill as well as what happened after Isabel Kabra was charged with murder. Nothing has been held back.

Seven Cahill agents came together to bring you this book, betraying their branches and their most deeply held beliefs. They did it because there is an enemy approaching far more powerful than the Cahills. Keep this black book close at all times, and be ready.

This book is part of a book series called 39 Clues .

There are 192 pages in this book. This book was published 2010 by Scholastic US .

Rick Riordan is the author of the hugely popular Percy Jackson series. Penny Arlon writes children's nonfiction, taking inspiration from her own children. Her books range from preschool titles to family reference books, and include the Art Attack books, based on the award-winning CITV (UK) children's television program, and all 14 titles in Dorling Kindersley's Eye Know series. She is the author of almost all the books in the Scholastic Discover More emergent and confident reader strands, which have won numerous accolades and prizes.