Die drei Fragezeichen (Original) is a 46-book series with 46 primary works first released in 1964 with contributions by Robert Arthur, William Arden, and 8 others.
1964 • 16 Readers • 165 pages • 3.6
1967 • 2 Readers • 164 pages • 3
1968 • 2 Readers • 184 pages • 3
1964 • 1 Reader • 169 pages • 4
1966 • 1 Reader • 139 pages • 4
1974 • 1 Reader • 139 pages • 4
1990 • 1 Reader • 117 pages • 3