The Thirty-Nine Steps is an adventure novel by Scottish author John Buchan. It was serialized in All-Story Weekly (June 5 and June 12, 1915) and Blackwood's Magazine (credited to "H de V.", July - September 1915) before being published in book form in October 1915 by William Blackwood and Sons, Edinburgh. It is the first of the five novels featuring Richard Hannay, an all-action hero with a stiff upper lip and a miraculous knack for getting himself out of tricky situations.

The novel has been the basis for many successful adaptations, including several films and a long-running stage play. In 2003, the book was listed on the BBC's The Big Read poll of the UK's "best-loved novels."

The Thirty-Nine Steps is one of the earliest examples of the '"man-on-the-run" thriller archetype subsequently adopted by film makers as a much-used plot device. In The Thirty-Nine Steps, Buchan holds up Richard Hannay as an example to his readers of an ordinary man who puts his country's interests before his own safety. The story was a great success with the men in the First World War trenches. One soldier wrote to Buchan, "The story is greatly appreciated in the midst of mud and rain and shells, and all that could make trench life depressing."

Hannay continued his adventures in four subsequent books. Two were set during the war, when he continued his undercover work against the Germans and their allies the Turks in Greenmantle (1916) and Mr Standfast (1919). The other two stories, The Three Hostages (1924) and The Island of Sheep (1936) were set in the postwar period, when Hannay's opponents were criminal gangs.

The novel has been adapted for multiple media; many of these versions depart significantly from the text-for example, by introducing a love interest absent from the original novel and inspired by Hitchcock's film. In most cases, the title is often abbreviated to The 39 Steps, but the full title is more commonly used for the book and 1978 film adaptation. (wikipedia.org)