Reading works of fiction can grow your vocabulary and lead to higher levels of emotional intelligence. For Kevin O'Leary and Mark Cuban, co-stars on ABC's "Shark Tank," fiction has also inspired ambition. Both entrepreneurs say classic novels written by Ayn Rand — a Russian-born author and strong advocate for free market principles — have impacted their perspectives and provided motivation for success.

"Atlas Shrugged" by Ayn Rand

O'Leary counts Rand's 1957 book, "Atlas Shrugged," as a favorite, he tells The New York Times Magazine. The book explores the relationship between acting in your own self interest and finding economic prosperity. It shaped O'Leary's impression of capitalism, he tells The Times. "I realized that in capitalism, either you believe in the intrinsic concept about the pursuit of wealth and why it's good for you, or you don't," he says. "I never question it. I never even think for a second that it was not the right path. "To me there is darkness and light. Capitalism is the light. Socialism is the darkness. Nothing could ever change my mind about that," he explains. Kevin O'Leary considers Rand a person to admire, according to a 2014 interview with The Montreal Gazette. "She was a hardcore capitalist," he says. "I'm slightly right of Attila the Hun so I appreciate her work."

"The Fountainhead" by Ayn Rand

Cuban is also a reader of Rand's work, but favors her 1943 novel "The Fountainhead." He's read the book, "three complete times, and untold number of little snippets and segments," he tells C-Span in a 2006 interview. "I'll pick it up when I need motivation, but then if I read too far I get too much motivation, and I get too jittery so I have to put it down." To him, the dedication of the characters to overcome challenges is encouraging. "Anybody who started a business and built a business knows there's going to be lots of times when you feel beaten down, and you need some motivation, and that's when I turn to that book among others," Cuban continues. "The Fountainhead" similarly explores topics of "rational selfishness," an ideology that later became known as objectivism. Cuban says he didn't read into the political message of Rand's work but found motivation in her characters. "I didn't buy into her political philosophy, like 'all government is bad,' and pure libertarianism," Cuban explains on a 2017 episode of "The Jamie Weinstein Show" podcast. "When you have a protagonist like Howard Roark, that just fired me up," Cuban says about the book, "He was true to himself. And to me, that was the message that I took home." Don't miss: Mark Cuban: The 3 best tips to save more money in 2018 Like this story? Like CNBC Make It on Facebook.