Introduction

The U.S. science Ph.D. seems to have hit a wall—hard. After decades of expansion, the number of scientists seeking research grants and research jobs appears, in the eyes of many, to have outstripped the money available to supply them. Cell biologist Richard McIntosh, former president of the American Society for Cell Biology, has described the situation as a “Malthusian crisis.” This special issue of Science examines the many effects of this crisis, from calls for Ph.D. “population control” to changes in graduate programs to make their graduates more marketable in an uncertain future.