Information on job characteristics and the people who perform those jobs is valuable for career guidance, reemployment counseling, workforce development, human resource management, and other purposes. In 1998. the U.S. Department of Labor launched the Occupational Information Network (O*NET), which consists of a content model (a framework for organizing occupational data) and an electronic database. The content model includes hundreds of descriptors of work and workers organized into categories, such as skills, knowledge, and work activities. Data on job titles are classified into 1,102 occupations. The National Center for O*NET Development (O*NET Center) collects data related to these occupations continually. In 2008, DOL requested that the National Academies review O*NET and suggest future directions. In the present volume, the review committee provides and overview and evaluation of how O*NET is used; a review of linkages between O*NET, the Standard Occupational Classification System, and other data sets; and suggests improvements to O*NET, particularly in the areas of cost-effectiveness, efficiency, and timeliness.