Leisure Books was a mass market paperback publisher specializing in horror and thrillers that operated from 1957 to 2010. In the company's early years, it also published fantasy, science fiction, Westerns, and the Wildlife Treasury card series. Leisure Books offered a book sales club service. Typically two free books were provided as an initial inducement. After that two books were sent on a monthly basis. Readers would have ten days to keep or return. If kept there would be a discount on the purchase price.