Some of the names on the Giving Pledge list are nationally famous -- Gates, Buffett, Rockefeller, Bloomberg, Turner, Lucas, Pickens, and a few others. But most signers of the pledge are only renowned in a city, like Dallas or Tulsa, or even in a professional locale, like Wall Street.

So in the gallery that follows you'll find short profiles of several pledgers not well-known to the general citizenry but definitely to be reckoned with in the worlds of wealth and philanthropy.

Last updated June 20 2011: 4:17 PM ET