Mary K. Bonsteel Tachau, a long-time history professor at the University of Louisville, died on October 1 at the age of 64.

Dr. Tachau received her B.A. from Oberlin College in 1948, her M.A. from the University of Louisville in 1958, and her Ph.D. from the University of Kentucky in 1972. She started teaching at the University of Louisville as an instructor in 1958 and remained there throughout her career. At the time of her retirement in July 1990 she held the title of professor emerita.

At various times she served as the university ombudsman, as the chairwoman of the university's Committee on the Status of Women, and, from 1974 to 1977, as the first chairwoman of the university's history department. In 1976, as chairwoman of the university senate, she was the first woman to sit on the University of Louisville's board of trustees.

Her specialties were American constitutional and legal history, and, in a description she accepted, "rocking the boat." Among her many publications are Federal Courts in the Early Republic: Kentucky 1789–1816; "The Whiskey Rebellion in Kentucky: A Forgotten Episode of Civil Disobedience," Journal of the Early Republic, Fall 1982; "Another Look at the Whiskey Rebellion," The Whiskey Rebellion: Past and Present Perspectives; "George Washington and the Reputation of Edmund Randolph," Journal of American History, June 1986; and "Women in the Southern Constitutional Tradition," The South and the American Constitutional Tradition, 1988.

Dr. Tachau was the recipient of numerous fellowships, including the American Bar Foundation Fellowship in Legal History (1977–78), a NEH fellowship for Independent Study and Research (1981–82), a Philadelphia Center for Early American Studies travel grant (1983), and a NEH Travel to Collections grant (1984).

Dr. Tachau received the University of Louisville College of Arts and Sciences Outstanding Alumna Award in 1964. In 1979 she was awarded the Kentucky Historical Society's Governor's Award, and in 1983 she received the Society for the History of the Early American Republic's Best Article Award. She received two additional University of Louisville awards: the Outstanding Service Award in 1985 and the Outstanding Teacher Award in 1988.

She was active in the ACLU as a board member (1960–76) and chair (1973–75) of the Kentucky Chapter. She was also a member of the state Commission on Human Rights and the Federal Judicial Selection Committee of Kentucky. The academic organizations to which Dr. Tachau belonged include the American Historical Association, the American Association of University Professors, the American Society for Legal History, the Kentucky Historical Society, the Organization of American Historians, and the Society for History of the Early American Republic. At the time of her death she was a council member of the American Historical Association, Vice President of the Teaching Division, and a member of the Finance Committee. She had also been on the American Historical Association's Special Committee on the Bicentennial Era from 1981–88.

She is survived by her husband, Eric Tachau; three children (Katherine Tachau of Iowa City, IA; Susan Tachau of Philadelphia, PA; and David Tachau of Louisville, KY); her mother, Mrs. Carl Neitzel of Cleveland, OH; a brother, William Bonsteel, of Washington, DC; a sister, Carol Ratliff, of Detroit, MI; and four grandchildren.