In the turbulent era from 1890 to the late 1930s, Detroit emerged as a leading industrial and urban center and endured the crushing social and economic challenges of the Great Depression. It was during these years that Tracy W. McGregor, with the assistance of his wife, Katherine Whitney McGregor, established himself as a philanthropist and community leader. Though public buildings and a charitable foundation bear their names, relatively little is known about the private-minded McGregors, who avoided newspaper interviews or public exposure whenever possible. In Tracy W. McGregor, Philip P. Mason scours the archival collections of the University of Michigan, Wayne State University, the State of Michigan, the Burton Historical Collection of the Detroit Public Library and the Library of Congress to provide a comprehensive look at the remarkable work of the McGregors. Mason examines McGregor's successful campaigns to reform the political, judicial, and educational institutions in Detroit, as well as his establishment of mental health, correctional, and health care facilities in Michigan. In addition, Mason surveys McGregor's work as president of the prestigious Merrill-Palmer Institute and his major collection of Americana books, which now serves as the core of the University of Virginia Research Library. In all, Mason shows how Tracy McGregor was able to establish a mission for homeless men, permanently endow a major foundation, and lead in the creation and support of a variety of charitable agencies without governmental assistance and with only the support of nascent philanthropic and business networks. For Detroit historians and those interested in philanthropy and social activism, Tracy W. McGregor will be enlightening reading.