The great wealth transfer has begun. In the next two to three decades, baby boomers, the wealthiest generation in American history, will pass down an estimated $68 trillion to their children and grandchildren. Baby-boomer philanthropy is flourishing, but only rarely do donors focus their efforts on reversing society's moral and spiritual ills. Among the notable exceptions are David Green and his family, founders of the Hobby Lobby arts-and-crafts stores. Green has invested billions in national and international nonprofits to help the downtrodden, while engendering three generations eager to bestow on others the wealth that might have been theirs.