Atlas Shrugged is more than three times the length of Built to Last and features far steamier love scenes. But the two books share this: They are among the all-time favorite reads of business leaders. Published 50 years ago this month, Ayn Rand's very magnum opus has inspired several generations of entrepreneurs to unleash their inner titans of industry.

The novel recounts a battle for--as oxymoronic as it sounds--the soul of the U.S. economy. On one side are the "producers," who use brain or brawn to invent, to create wealth and change the world. On the other side are "looters" and "moochers": academics, government officials, and underachievers seeking to live off the sweat of others. The plot turns on efforts by dauntless railroad executive Dagny Taggart and her lover, the resolute industrialist Henry Rearden, to keep their empires afloat while the enemies of progress thwart them at every turn. Meanwhile, the nation's most talented individuals are mysteriously disappearing, lured by enigmatic visionary John Galt to Colorado, where they withhold their talents from a society they see as hopelessly corrupt.

Atlas Shrugged was largely panned upon publication and still has its detractors. ("Obviously the high priestess of free enterprise never met the men of Enron, Adelphia, and WorldCom," scoffed Arianna Huffington in her book Pigs at the Trough.) But countless entrepreneurs credit the book with inspiring them to start their businesses and persevere in tough times. In honor of the novel's 50th anniversary, Inc. asked some Rand-obsessed entrepreneurs how Atlas Shrugged changed their lives.

"Atlas Shrugged is like Shakespeare for the businessperson. The first time I read it I was around 20, and it took me six months because I wanted to savor each page. I'm a perfectionist, and Atlas Shrugged made me want to create an organization that reflected my perfectionism. I give my clients the absolute best. Most of them know that. But if they don't know it that's okay: I know it. I was also influenced by how the bosses in the book treat their employees. Am I responsible for my people? Without question. But at the end of the day, they are responsible for generating superior product to keep a job at this company. The company doesn't exist to put food on their plates."

David Morrison, founder and CEO of Twentysomething, a marketing firm that targets young adults, based in Philadelphia

"My partner in my first start-up turned me on to Atlas Shrugged, and everything in the book resonated. We had just gotten a notice from the Ohio government saying we hadn't paid unemployment insurance and they were going to close our business. They were going to unemploy everybody because we hadn't paid unemployment insurance. It was so ironic, so anti-Rand. Today, my middle child is named Kian Rand O'Connor after Ayn Rand."

Kevin O'Connor, co-founder of DoubleClick, the digital advertising company, and O'Connor Ventures, in Santa Barbara, California

"I created The Atlasphere, a social networking and dating site for Ayn Rand fans, after I was approached by a gentleman who said, 'When I go to a new city and I need to find a lawyer or a realtor, I'd like to have a directory of people who love Ayn Rand's ideas.' People like to do business with others who share their philosophy. Rand is a starting place for trust."

Joshua Zader, founder of Zoom Strategies, a Web-development business in Albuquerque, and the host of The Atlasphere

"I reread Atlas Shrugged in 2001. At the time, my husband and I had been working at 9 to 5 jobs for almost 20 years and we weren't happy. We took inspiration from what Rand says about how it's your moral obligation to pursue your own happiness. People look at this company and at our lifestyle now and they say, 'Oh, aren't you lucky.' No, we're not lucky. We made a fortune, but we took risks to do so. We sacrificed security in order to do our own thing. Atlas Shrugged encouraged us to do that."

Moira Mattingly, president of Summit Solutions, a technology consultant to the military and intelligence communities, based in Ellicott City, Maryland

"When I was in high school, I thought big business was evil. Atlas Shrugged rewired my brain. I remember reading about an airline that had to sell off gates at Heathrow for a merger to go through. This company was so successful that it managed to buy another company. It was providing a better service. And it's supposed to give gates to companies that aren't as good? That doesn't make sense. And the minute I thought, 'Let the market decide,' a cold shiver went up my spine. I thought, 'She's in my head now!"

Rich Brooks, president and founder of Flyte New Media, an Internet marketing company in Portland, Maine

"My partner and I named our company after John Galt because he symbolized for us the ability to assemble the best and brightest minds in order to change the world. Today, we include slides about John Galt in our customer training material and there are 'Producer or Looter?' signs up around the office. Anybody who wants to start a business should read Atlas Shrugged to understand what they'll be facing. It's about all these challenges and how, in spite of them, you wake up excited every morning about what you're going to do that day."

Annemarie Omrod, co-founder and CEO of John Galt Solutions, a logistics software company based in Chicago