Titles by L. Sprague de Camp marked with tag: unknown worlds
- 1950 - The Castle of Iron with Fletcher Pratt
- 1948 - The Carnelian Cube with Fletcher Pratt
- 1942 - The Land of Unreason with Fletcher Pratt
- 1941 - Lest Darkness Fall
- 1941 - The Incomplete Enchanter with Fletcher Pratt