Which books? Will it be one book per movie, or all the books in one movie? I've been wondering this because it's "The 39 Clues: The Movie" and not "The 39 Clues: The Maze of Bones". Another possibility is they do 3 a movie
Books 1, 2 and 3 = Movie 1,
4,5 and 6 = Movie 2,
7,8 and 9 = Movie 3
10 and 11 = Movie 4
CvV Books 1,2 and 3 = CvV Movie 1
4,5 and 6 = CvV Movie 2
Just something to think about.