The Necronomicon

Lovecraft wrote it as pure fiction from 1922 onward and repeatedly confirmed in letters to friends that it did not exist. A 1977 commercial version has since sold hundreds of thousands of copies on the strength of readers mistaking it for the genuine ancient text.

H. P. Lovecraft's own correspondence confirming the Necronomicon's invention (from 1922); the 1977 'Simon' Necronomicon