Some might think: How could they do it? How could someone like Mike Hughes, "an offbeat guy, but a good one," according to Daily Beast journalist Kelly Weill, believe that the Earth is flat and set out to prove it by "experimenting with amateur jet propulsion" to launch himself into low orbit and "decide the planet's shape for himself"?

Then again, how could someone believe any of the conspiracy theories that catch on among segments of the population, such as that the current pandemic is a hoax, or that the 2020 election was tainted, a lie that has produced an "increasingly ludicrous series" of improbable explanations?

Weill tries to find out why in "Off the Edge," a surprisingly even-handed book, the title of which perfectly encapsulates disturbing implications of conspiracy theorists and their beliefs. To many observers, they have gone off the edge, but their beliefs have moved from the fringes to the centers of power, with elected officials, including presidents, amplifying their messages.

Weill is critical of conspiracy theorists but tries to understand them, as when she explains, "conspiracy theories help us feel safe by providing an explanation for things that feel incomprehensible and beyond our control." She adds, however, that that "can influence us in measurably silly ways."

The book begins with the history of the Flat Earth movement, starting in 1838 with Manea Fen, a "short-lived socialist commune" among Cambridgeshire laborers led by Samuel Birley Rowbotham, who was usually "high off his mind on laughing gas." Rowbotham was a shady character, first tossed out of the commune over a sex scandal and later becoming a huckster who sold miracle cures. One cure promised immortality through a concoction of phosphoric acid & lime — in other words, soda.

Weill devotes much of the book to the various forms of media throughout history that have allowed conspiracists to disseminate their message, from newspapers in Rowbotham's day to today's social media and sites like YouTube.

Other chapters mix poignant stories, including those of Flat Earthers who become objects "of ridicule and social rejection," with tales of darker factions, such as the Flat Earth contingent that "regards the Holocaust as a hoax" and engages in "undiluted Nazism."

Despite moments of humor, the tone of "Off the Edge" is elegiac, with sadness over the consequences of Flat Earthers' beliefs, among them the fate of Mike Hughes. Not one to let setbacks dissuade him, he kept tinkering with jet propulsion until he developed a homemade rocket that would let him "fly to the atmosphere's upper reaches in order to take a picture that would prove the planet's flatness." In February 2020, he was killed in a launch.

Michael Magras is a freelance book critic. His work has appeared in the Washington Post, Times Literary Supplement, Pittsburgh Post-Gazette, Kirkus Reviews and BookPage.

Off the Edge
By: Kelly Weill.
Publisher: Algonquin Books, 256 pages, $27.95.