Entrepreneurial companies have long been the engine driving our nation's economy--and when you consider the stellar successes displayed by the companies in our annual Hot 100 list of the nation's top fast-growth businesses, it's not hard to see why. Despite a roller coaster economy and a global marketplace that grows more competitive by the day, all our Hot 100 companies have added jobs to the American economy since their inception.

This is our 14th Hot 100 listing, and in some previous years, one industry (such as technology) easily dominated the group. It wasn't so this year. In fact, a quick look at these 100 companies reveals that they encompass an astonishing range of products and services--from hanger manufacturing and food sales to energy suppliers and defense contractors.

That same diversity is reflected in the individual entrepreneurs behind each company's success story. Whatever their backgrounds or industries, however, these fast-growth entrepreneurs share two common traits: the ambition to set far-reaching goals and the drive to make those goals a reality.

Throughout the history of this country, entrepreneurs have helped it thrive. With the global economy still uncertain, the innovative spirit of entrepreneurs like those in our Hot 100 listing is more crucial than ever in helping the United States remain competitive. If the strengths of our Hot 100 entrepreneurs are any indication, we have great faith in the future.

This is how it all begins: The Hot 100 ranking is compiled with the help of CentrisPoint, a research organization. Entrepreneur and CentrisPoint started with CentrisPoint's database of nearly 21 million U.S. businesses and considered only those businesses that met the following criteria:

• Must have been founded no earlier than 1999 and no later than 2003
• Company sales in 2003 must be $100,000 or greater; 2007 sales must not exceed $1 billion
• Must have positive job growth between 2003 and 2007
• Must have a minimum level of sales growth or a sales growth quantifier of 1 or higher between 2003 and 2007; the growth quantifier is a measurement that combines percentage and absolute growth.

Only 64,000 businesses--or 0.3 percent of the nearly 21 million businesses--met the above criteria. Entrepreneur then contacted the businesses with the greatest growth to confirm eligibility. To be eligible, the founder must be actively involved in the company, the company cannot be a spinoff or a division of a larger company, and company sales for 2007 must be at least $1 million. From this list, the Hot 100 was selected.

Entrepreneur research conducted by Maria Anton Conley, Emily Weisburg and Tracy Stapp, with additional assistance from Kristen Henning, Jake Kilroy, Adam Salazar and Mallory Somerset.

CentrisPoint is a leading provider of economic and business data, research, and information. From its Washington, DC, headquarters, CentrisPoint serves businesses and governments worldwide, offering high-quality insights into the U.S. economy, the companies that compose it and the forces that shape it.