In recent years, much attention has focused on the growth of nonstandard and contingent employment (including part-time work), which involves up to 30 percent of the total U.S. labor force. There is little agreement on either the causes or the effects of this trend. Some researchers emphasize the advantages: employees may explore the job market and obtain work that does not necessarily involve rigid schedules, while employers enjoy greater flexibility and lower costs. Others point to the disadvantages for employees, such as lack of job security, fewer benefits and chances for promotion, and often lower wages. Drawbacks for employers include a workforce that has little chance to develop firm-specific knowledge or loyalty.Chapters in Nonstandard Work: The Nature and Challenges of Emerging Employment Arrangements carefully analyze the extent and nature of various nonstandard work arrangements; their advantages and disadvantages for employees and employers; the demographic, industrial, and occupational distribution of such positions; and the question of whether standard employment itself is changing. Some contributors consider how innovative labor market intermediaries and unions might expand opportunities for workers while also helping firms to raise their productivity.