Geiger, John, 1960-

John Grigsby Geiger is an American-born Canadian author and shipwreck hunter. He is best known for his book The Third Man Factor: Surviving the Impossible, which popularized the concept of the "third man", an incorporeal being that aids people under extreme duress. The book is the basis for a National Geographic Channel video entitled Explorer: The Angel Effect, in which Geiger appears. In turn, a second book on the topic, based on, and taking its name from the National Geographic video, was published in 2013. His other works include the international bestseller Frozen in Time: The Fate of the Franklin Expedition. In 2024, Geiger led a Royal Canadian Geographical Society expedition that located Ernest Shackleton's last ship, Quest (ship). Geiger was appointed Chief Executive Officer of the Royal Canadian Geographical Society in 2013. Geiger was born in Ithaca, New York, in the United States, but grew up in Edmonton, Alberta in Canada, studying history at the University of Alberta. Geiger was made a member of the Order of Canada in 2020.