Life has many surprises. One of the best surprises is meeting a caring mentor, an encouraging collaborator, or an enthusiastic friend. This volume is a tribute to P- fessor Michael K. Sain, who is such a teacher,colleague,and friend.On the beautiful fall day of October 27, 2007, friends, families, colleagues, and former students ga- ered at a workshop held in Notre Dame, Indiana. This workshop brought together many people whose lives have been touched by Mike to celebrate his milestone 70th birthday, and to congratulate him on his contributions in the elds of systems, c- cuits, and control. Mike was born on March 22, 1937, in St. Louis, Missouri. After obtaining his B.S.E.E. and M.S.E.E. at St. Louis University, he went on to study at the University of Illinois at Urbana-Champaignfor his doctoral degree. With his Ph.D. degree c- plete, he came to the University of Notre Dame in 1965 as an assistant professor. He became an associate professor in 1968, a full professor in 1972, and the Frank M. Freimann Chair in Electrical Engineering in 1982. He has remained at and loved the University of Notre Dame for over 40 years. Mike also held a number of consu- ing jobs throughout his career. Most notably, he consulted with the Energy Controls Division of Allied-Bendix Aerospace from 1976 to 1988 and the North American Operations branch of the Research and Development Laboratory of General Motors Corporation for a decade, 1984–1994.