We adore magic for its ability to boggle our minds with seemingly impossible feats. Usually it’s all in the name of entertainment and good fun, but there are less conscientious performers who use their skills in deception for more dubious purposes. For those charlatans and quacks, James Randi is your worst nightmare.

Born Randall James Hamilton Zwinge in Toronto on August 7, 1928, he’s spent many decades working in magic. He renamed himself James Randi, or sometimes The Amazing Randi, for his performances as a magician and escape artist. As a child, he was interested in mathematics as well as magic, and that translated into an act that was always firmly grounded in reality. He never credited his accomplishments to supernatural powers, but insisted that there was a logical solution to every trick.

That focus on reality led him to discredit several popular performers over the years who did claim to have a more mystical or divine power at their control. One famous example was his takedown of Peter Popoff in the 1980s. Popoff claimed that he could eliminate diseases and ailments from devout believers, who were willing to pony up vast sums of money for the privilege. Randi was able to tap into the radio transmissions between Popoff and his wife that allowed the phony faith healer to claim psychic insights. With a little help from fellow magician Johnny Carson, better known for his career as a Tonight Show host, Randi was able to gain a wide audience for his exposés. 

In addition to his work in magic and uncovering frauds, Randi is also a prolific author and the subject of the 2014 documentary An Honest Liar. And at 89, he’s still active and working.