Die drei Fragezeichen (Hörbücher) is a 5-book series with 5 released primary works first released in 1964 with contributions by William Arden, Robert Arthur, Alfred Hitchcock, Jens Wawrczeck, and M.V. Carey.
#19 of 43 in Alfred Hitchcock and The Three Investigators
1973 • 2 Readers • 148 pages • 4
#2 of 43 in Alfred Hitchcock and The Three Investigators
1964 • 2 Readers • 4
#12 of 43 in Alfred Hitchcock and The Three Investigators
1969 • 4 Readers • 126 pages • 3
#17 of 43 in Alfred Hitchcock and The Three Investigators
1972 • 2 Readers • 159 pages • 3.5
#3 of 43 in Alfred Hitchcock and The Three Investigators
1965 • 7 Readers • 180 pages • 3.3