The National Book League was a precursor to the current Booktrust, and was set up in 1924 by the Society of Bookmen in order to promote reading, particularly among the young. To that end, the NBL issued Reader's Guides on a variety of subjects, each written by an author with expertise in that field and containing an annotated bibliography of recommended titles on the subject. In this guide, first published in 1958, W. B. Stevenson divides his bibliography of recommended mystery titles into 'The Old Masters' and 'The Moderns', with an extra section for books about detective fiction. Some of the books recommended remain classics of the genre.