The breadth of what can be meant by the word “hoax” makes the concept — and consequences — worthy of renewed study. Michelle E. Ainsworth reviews Bunk: The Rise of Hoaxes, Humbug, Plagiarists, Phonies, Post-Facts, and Fake News by Kevin Young and Hoax: A History of Deception: 5000 Years of Fakes, Forgeries, and Fallacies by Ian Tattersall and Peter Nevraumont.