Selkirk was a buccaneer who sailed the South Seas on looting expeditions for gold and treasure. In 1703 he joined an expedition whose object was to plunder French and Spanish ships. Eventually they reached the island of Juan Fernandez, off the coast of Chile, where Selkirk opted to maroon himself. Suddenly solitude and silence were imposed, and his only relationship was with the island and with himself. He learnt to kill goats with cudgels and use their skins for coats and shoes. He hollowed out a canoe and circumnavigated the island. In 1709 Selkirk spotted two ships from his cliff-top lookout. They saw his fire and the next morning landed on Juan Fernandez - to be greeted by an unrecognisable savage-looking man incoherent with emotion. He sailed back with them to civilisation where he 'bewailed his return to the world'. Selkirk died in 1720 back at sea, of yellow fever.
Diana Souhami is the author of many widely acclaimed books, and she has also written plays for radio and television. She won the Whitbread Biography Award for Selkirk's Island.