The existential tension of a book of 100 facts about Boris Johnson is the man’s relationship to facts. The product of Britain’s top schools, he clearly knows better. But he has thrived less through displays of a hard-won and formidable erudition than by shading, exaggerating, or outright misstating the truth. Although he idolizes Winston Churchill, he has much more in common with US President Donald Trump. By creating a brand, a shtick, a persona, BoJo has transformed himself from a disgraced journalist into the most popular politician in Britain. Known for introducing Boris Bikes and Boris Buses while Mayor of London, Johnson’s most lasting legacy is likely to stem from his creation of Boris Facts, assertions of verisimilitude instead of veracity. By propagating these quasi-truths, an Old Etonian who had spent years living abroad managed to become, improbably, a champion of Little England, a motive force behind Brexit, and Prime Minister of the United Kingdom. His story, like the man himself, is fascinating, hilarious and scarcely believable.