Across the United States, millionaires and billionaires are increasingly stepping in with private money to try to solve problems that were once largely or exclusively the purview of government. In Detroit, philanthropic dollars helped build a streetcar system. In Kalamazoo, Mich., donors are underwriting college tuition programs. Elsewhere, philanthropists are funding the mapping of all cells in the human body to try to stamp out disease and pouring money into preventing obesity. Yet few if any of today's megadonors are involved in as many programs targeting the poor in one city as [George] Kaiser. The oil and gas industrialist believes that every child deserves a chance to succeed and that effectively spent charitable dollars ... can unlock their potential. His foundation has given away more than $1 billion over the past decade, almost all of it in Tulsa, [Okla.]. Over the next decade, his foundation wants to target every poor child born in Tulsa, from birth until third grade, so that a patchwork of public programs - prenatal care, parenting classes, child care - becomes a seamless quilt. They're making a very big bet in one community on a comprehensive strategy that can be truly transformative," says Nancy Roob, chief executive officer of the New York-based Edna McConnell Clark Foundation. The idea behind all these efforts - fighting poverty with philanthropic wealth - is one that holds great promise in an era of dazzling private fortunes, yawning economic inequality, and public-sector austerity.