Robert K. Yin, PhD, is Chairman of the Board and CEO of COSMOS Corporation, an applied research and social science firm that has been in operation since 1980. COSMOS has successfully completed hundreds of projects for government agencies, private foundations, and other entrepreneurial and nonprofit organizations. Dr. Yin has authored five books--including Case Study Research, now in its fifth edition--and over 100 peer-reviewed articles. His research has covered a wide array of fields, such as primary, secondary, and postsecondary education; health promotion, HIV/AIDS prevention, and substance abuse prevention; organizational development and program evaluation; neighborhood, community, and urban development; and technological innovation and communications.