In the interest of learning more about contracting as a method of transit service delivery, the 1998 Transportation Equity Act for the 21st Century (TEA-21) called on the Transportation Research Board (TRB) to conduct a study of contracting by recipients of federal transit grants. TEA-21 called for an examination of the extent and practice of transit service contracting and its effects on operating costs, customer service, safety, and other aspects of service quality and quantity. To conduct the study, TRB convened a 12-member committee of experts in public transportation management, labor, economics, and public policy. In carrying out the study, the committee reviewed previous reports on transit service contracting; conducted its own nationwide survey of public transit systems and their general managers; and interviewed transit managers, labor union leaders, contractors, and members of transit policy boards. Resulting findings and conclusions are summarized in this report, along with additional insights and ideas for follow-on study. The contents are organized as follows: (1) Introduction; (2) Public and Private Provision of Transit in the United States; (3) Conceptual Framework and Previous Studies on Contracting; (4) Transit Service Contracting in the United States: Extent and Practice; (5) Transit Contracting Experiences and Advice from General Managers; and (6) Summary and Assessment.