Hardy-guttene is a 38-book series with 38 primary works first released in 1920 with contributions by Franklin W. Dixon, Jerrold Mundis, and Leslie H. Morrill.
1927 • 35 Readers • 214 pages • 3.5
1927 • 20 Readers • 138 pages • 3.5
1982 • 1 Reader • 181 pages • 3