49. Leo and Kay Drey

Schram Glass heir, silviculture

2003-07 Given or Pledged: $180 million
Favored Causes: Conservation
Estimated Lifetime Giving*: $180 million

The Dreys gifted a Chicago-sized swath of Ozark forest land, valued at $180 million, to their St. Louis foundation for the "pioneering of proper land management and the enjoyment of outdoor enthusiasts." Beyond conservation, the thrifty Missouri couple gives generously to support causes ranging from civil liberties to the arts.

*Based on public records and interviews with donors
Data: BusinessWeek, GuideStar, The Chronicle of Philanthropy, The Center on Philanthropy at Indiana University