"Greenmantle", by John Buchan, is actually based on a remarkable, if little-known, aspect of German propaganda during World War I. It involved Kaiser Wilhelm declaring himself a convert to Islam, a leader of "jihad", as a tactic for winning the support of the Muslim territories under British control and thus fomenting an anti-British revolution. Richard Hannay, Buchan's intrepid hero from "The Thirty-Nine Steps", is the man entrusted to stop this plan from being carried out, and his adventure takes him from London, to Holland and Turkey and finally to the Russian border for a spectacular climax. Complaints have been made about Buchan's racist and jingo-imperialist biases, as the novel easily betrays the sentiments of a la "dominion over palm and pine." However, a fiction-writer may, under a certain poetic license, attack creeds, doctrines, persons and institutions with impunity; moreover, a writer must be seen as a product of his age. This racy, lively, energetic novel is best appreciated as an excellent work of light literature. The conclusion is an undeniably exciting confrontation, including the charge of Cossack cavalry, as Hannay engages in the final showdown between the two German villains, the gross Stumm and the evil beauty, Hilda von Einem.