Mark Cuban started with just $60 in his pocket before launching his first business, MicroSolutions, which he sold to CompuServe for $6 million. Five years later, the entrepreneur co-founded Broadcast.com, which Yahoo bought for nearly $6 billion.

Today, Cuban owns the Dallas Mavericks, stars on ABC's "Shark Tank" and is worth more than $3 billion.

If you asked the businessman about one of the he's ever made along the way, his simple answer may surprise you: Books.

"I used to love to walk through bookstores," Cuban tells Vanity Fair. "If there was something that caught me eye and I thought it could give me one idea — to spend $30 to give one idea that could help propel me and make my businesses better, it was a bargain."