We didn't have to look far for the theme for this year's Top 50 Businesses in Pittsburgh section.

The Allegheny Conference on Community Development is spearheading the effort to make sure that Pittsburghers near and far know about the city's 250th birthday.

Local companies and organizations are joining in the "Pittsburgh 250: Imagine What You Can Do Here" marketing initiative. The list of sponsors at the celebration's official Web site (• www.imaginepittsburgh.com) reads like a who's who of Pittsburgh business.

For the numbers crunchers and list makers, the section ranks the Top 50 public companies on our usual measures -- revenue, change in revenue, net income, change in net income, change in stock price, return on equity and market value.

We also look at local private companies and companies based outside the area that have a significant local presence.

Then there is our snapshot of local foundations, colleges and universities, the arts and health care companies.

And we continue our examination of local public companies with women in positions of authority.

We hope this section is a must-read for business professionals and anyone else who wants to understand where the city's business community has been, where it stands and where it could be heading in the next 250 years.