Case management has been variously classified as a skill group, a core function, service coordination, or a network of "friendly neighbors." Although it defies precise definition, case management generally can be described as a coordinated approach to the delivery of health, substance abuse, mental health, and social services, linking clients with appropriate services to address specific needs and achieve stated goals. The Consensus Panel that developed this TIP believes that case management lends itself to the treatment of substance abuse, particularly for clients with other disorders and conditions who require multiple services over extended periods of time and who face difficulty in gaining access to those services. This document details the factors that programs should consider as they decide to implement case management or modify their current case management activities. This summary is excerpted from the main text, in which references to the research appear.