There were many stories of real-life castaways in Defoe's time. Defoe's immediate inspiration for Crusoe is usually thought to be a Scottish sailor named Alexander Selkirk, who was rescued in 1709 by Woodes Rogers' expedition after four years on the uninhabited island of Más a Tierra in the Juan Fernández Islands off the Chilean coast. Rogers' "Cruising Voyage" was published in 1712, with an account of Alexander Selkirk's ordeal. However, Robinson Crusoe is far from a copy of Woodes Rogers' account: Selkirk was marooned at his own request, while Crusoe was shipwrecked; the islands are different; Selkirk lived alone for the whole time, while Crusoe found companions; while Selkirk stayed on his island for four years, not twenty-eight. Furthermore, much of the appeal of Defoe's novel is the detailed and captivating account of Crusoe's thoughts, occupations and activities which goes far beyond that of Rogers' basic descriptions of Selkirk, which account for only a few pages. However, one must not forget that Defoe considered himself as the editor of the story. He was adamant to maintain his claim that the real author Robinson Crusoe had been a person still alive in 1719–20.
Tim Severin's book Seeking Robinson Crusoe (2002) unravels a much wider and more plausible range of potential sources of inspiration, and concludes by identifying castaway surgeon Henry Pitman as the most likely. An employee of the Duke of Monmouth, Pitman played a part in the Monmouth Rebellion. His short book about his desperate escape from a Caribbean penal colony, followed by his shipwrecking and subsequent desert island misadventures, was published by J. Taylor of Paternoster Row, London, whose son William Taylor later published Defoe's novel. Severin argues that since Pitman appears to have lived in the lodgings above the father's publishing house and that Defoe himself was a mercer in the area at the time, Defoe may have met Pitman in person and learned of his experiences first-hand, or possibly through submission of a draft.
Severin also discusses another publicised case of a marooned man named only as Will, of the Miskito people of Central America, who may have led to the depiction of Man Friday.