Mumintrollen is a 10-book series with 9 primary works first released in 1945 with contributions by Tove Jansson, David McDuff, and 5 others.
1945 • 23 Readers • 52 pages • 3.9
1948 • 12 Readers • 176 pages • 4.5
1962 • 6 Readers • 4
1962 • 1 Reader • 79 pages