The true story of a con artist who conducted surgeries, ran a prison, taught college, and more

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Does this guy look trustworthy?

When writing her fantastic exploration into the psychology of con artistry, "The Confidence Game: Why We Fall for It ... Every Time," Maria Konnikova stopped meeting with the thieves, imposters, and in some cases, psychopaths she was writing about.

"They are really good; they are really charismatic. Even if you know they're bad people, you walk away thinking they're good people," she tells Business Insider. "And it's really scary to see that happening - it's not pleasant, because it really makes you realize that it's just so easy for people to fall for their lines."

But there are some con artists that Konnikova just couldn't turn down an opportunity to meet, were it still possible.

"I totally want to meet Demara," she says, referring to Ferdinand Waldo Demara, a character she follows throughout the book. "That guy was so good."

Keep scrolling to learn about the man who may have been the most successful con artist in history.