. . . . . . . . . . . . . . "None"@en . . . . . . . . "The Black Book of Buried Secrets"@en . "The Black Book of Buried Secrets is a bonus book in The 39 Clues series released on October 26, 2010. It was writen by Mallory Kass and contains an introduction by Rick Riordan."@en . . "The Black Book of Buried Secrets is a bonus book in The 39 Clues series released on October 26, 2010. It was writen by Mallory Kass and contains an introduction by Rick Riordan."@en . . . . . . . . "The Black Book of Buried Secrets"@en . . . . "2010-10-26"^^ . . . . . . . . . "192"^^ . . . . .