Over 20 million people are working part-time in the United States, more than six million of them involuntarily. Both Time and Fortune magazines have run recent cover stories about this constrained faction of the workforce, who tend to earn on average 40 percent less than full-time workers. Addressing this disturbing trend, Chris Tilly presents a current, in-depth analysis of how US businesses use part-time employment, and why they are using it more and more. Worker demand for part-time jobs peaked more than twenty years ago, but employers' desires for cheap labor and schedule flexibility have continued to drive the long-term growth of part-time jobs. Tilly argues that this growth is a reaction to the expanding trade and service industries, which, by their nature, depend on part-time workers. Examining the nature and purposes of the different types of part-time employment, he explores the roots of part-time jobs in the organization of work, and the inadequacies of existing public policies on part-time employment. Using not only statistical analysis but over eighty interviews with employers in the retail and insurance industries, Tilly suggests new approaches to providing flexibility without insecurity.