The Black Book of Buried Secrets
A book to save the world
39 Clues group, Introduction by Rick Riordan
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The Black Book of Buried Secrets, although often considered the eleventh book, is in fact a stand-alone book full of facts about The 39 Clues.


The book in your hands is the ultimate source of Cahill knowledge. It contains every buried secret, every 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 most deeply held beliefs. They did it because there is an enemy approaching, far more powerful than the Cahills. Destroy after reading.

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