The theme for this year's Top 50 in Business section is "Going for the Green: Finding Growth Through The Green Movement." But in the larger sense, it's about sustainability. It is how businesses today ensure their long-term viability by controlling or reducing their reliance on resources.

It's a story that Pittsburgh is uniquely positioned to tell.

Our reputation for years was driven by our past. We were an industrial hub whose success was marked by the smoke from factories. If you couldn't see the sun, that meant people had jobs.

But that success wasn't sustainable, as the recession of the 1980s proved. The changes that the region was forced to make in the wake of that economic storm set us in better stead to survive the recent economic tsunami.

The attention Pittsburgh gained as it weathered the recession better than most other parts of the country also has focused on the region's commitment to sustainability.

This section examines the region's deep roots in the environmental movement and the importance of sustainability to its future as well as the balancing act companies must be aware of when they try to be more environmentally conscious.

We also look at the role of the green movement in different sectors of the local economy. It isn't hard to find stories of the innovative and sometimes surprising things companies are doing in the Pittsburgh region. In fact, there were so many examples we didn't have room the share them all. We have set up a forum at post-gazette.com to collect more stories of the things companies are doing in the name of sustainability.

Of course, we are continuing the annual benchmark of local companies ranked by the same measures we've been using for years -- revenue, change in revenue, net income, change in net income, change in stock price, return on equity and market value. The list is an interesting statistical dissection of the impact of the recession.

We also examine local private companies and companies based outside the area that have a significant presence in southwestern Pennsylvania, foundations, colleges and universities, the arts and health care companies.

The annual Top 50 section is the culmination of months of work from reporters, photographers and artists. In addition to the journalists whose names appear in the section, Assistant Business Editors R.J. Hufnagel and Teresa Lindeman helped to shape the section and are in no small part responsible for its success.

Special recognition goes to reporter Len Boselovic for compiling the lists from company reports and his own research.

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