Lost Worlds is a collection of fantasy, horror and science fiction short stories by the American writer Clark Ashton Smith.

[1] In the 1991 book The Science-Fantasy Publishers: A Critical and Bibliographic History, the authors Jack L. Chalker and Mark Owings noted "superb stories".

[2] The New York Times reviewer Marjorie Farber declared, "What is most fascinating about the present volume is the sort of obfuscatory prose which readers of Weird Tales, etc.

are apparently willing to overcome for the sake of getting at whatever terror may lie at the end of the skull-dotted trail," concluding that Lost Worlds "cannot be read.

[4] Black Gate's Robert Burke Richardson wrote, "In Lost Worlds, the condition of an uncaring universe becomes not a case for despair, but rather for a weird and precious celebration.