It's not hard to understand why the writers and editors of the Inc. 500|5000 company profiles enjoy their jobs. What other gig would give you the chance to talk to the head of a 153-year-old construction company with 180 job sites around the world, or to one of the founders of a company that makes life support systems for space, or to a brewer who raps about beer in a hip hop ensemble called The Pain Relievaz -- all in the space of an afternoon?

Slightly fewer than half of the companies on this year's list are repeaters from last year. In what is perhaps a reflection of the sluggish economy, the total revenue on this year's list is less than last year's: $185.4 billion compared to $194.5 billion for the 2007 companies. But average three-year growth on the 2008 list is considerably higher: 334 percent compared to 295 percent for the 2007 list.

Another change that is probably related to the current economy is in the distribution of companies by industry. Last year's top two categories, Construction and Manufacturing, have been supplanted by IT Services and Business Services (last year's numbers three and four). Interestingly, this year's fastest-growing category is Energy, with a median growth rate of 287.5 percent. Eight of the 79 companies in Energy are involved with solar energy, with five more working with other alternative fuels. And perhaps not surprisingly, 10 of them are firms that help consumers and companies save money on their energy bills.

Geographically, not much has changed. The five states with the most Inc. 500|5000 companies are still California (led by the Advertising & Marketing industry), Texas (by IT Services), New York (Business Services and Advertising & Marketing), Florida (Business Services), and Virginia (IT Services), in that order. In the top ten, Georgia and Massachusetts slip from numbers six and seven to eight and nine, while Pennsylvania and Illinois rise to numbers six and seven from eight and ten. Regionally, the Midwest still has the most Inc. 500|5000 companies, while the Southeast takes the number two spot from the West. The top four metro areas stay the same: New York, Washington, Los Angeles, and Atlanta. But Chicago moves up from number seven to number five, while San Francisco slips from five to seven.

Our number one company on the list, Senior Whole Health, is, like last year's number one, Member Health, in the health insurance business. While MemberHealth manages Medicare Part D prescription drug plans, Senior Whole Health has a health care plan for special-needs customers that helps them navigate the Medicare and Medicaid labyrinths. (MemberHealth does not appear on this year's list because it was bought last year by Universal American Financial.)

A new company on the list is the largest ever to make the Inc. 5000 or Inc. 500: global construction firm CH2M Hill, with $5.8 billion in 2007 revenue (up from $3.1 billion in 2004). Among many other things, CH2M Hill is attacking the world's energy problems from all sides, buying up oil pipeline companies, and helping build Masdar City, the world's first zero-carbon, zero-waste city, in Abu Dhabi.

In the who'd-a-thunk-it department, this year's list is filled with intriguing companies: WineCommune sells wine online and IT systems to other wine-related companies; Starizon teaches executives how to create experiences for their customers in part by having them interact with actors playing the likes of Einstein, Jefferson, and Galileo; Superior Dock Systems makes floating boat docks and has grown from $1.5 million to $5.4 million over the last three years thanks to the floating-boat-dock needs of retirees buying property along the combined 1,200-mile shorelines of Lakes Keowee and Hartwell in South Carolina (yes, we do our best to tell you why all 5,000 companies are growing); PG Professional Golf fishes golf balls out of golf course ponds and lakes, refurbishes them, and resells them (and they've bought up 11 other companies that do the same thing!); and Dogtopia provides doggie day care.

In addition to the 5,000 profiles, we've got a wealth of feature articles about companies and trends on the list, and we'll be rolling out more in the months to come. Check out "When the Boss is an Adrenaline Junkie" to see the crazy and challenging things some of our Inc. 500|5000 CEOs do in their spare time, and 7 New Technology Marvels to see some of the coolest things made by the 5000 companies. Over the next several weeks look for the harrowing story of one CEO's escape from Iran, and an article about how an increasing number of companies are hiring retirees.

Lastly, we'll mention that thanks to IncBizNet, our online community that is open to all private companies and that every Inc. 500|5000 applicant becomes a part of, our journalistic enterprise is truly never-ending and participatory. IncBizNet showcases Inc. 500|5000 companies in discussions, blogs, press releases, and in-person get-togethers in cities across the country. There, the Inc. 500|5000 past, present, and future will be telling their stories every day for years to come.

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To see the names of the people who wrote, edited, and otherwise contributed to this year's list, please visit our Contributors page.