David L. Nelson is Professor in the Department of Biochemistry at the University of Wisconsin, Madison.  He is also the Academic Program Director for universitys Institute for Cross-college Biology Education.  born in Fairmont, Minnesota, received his BS in chemistry and biology from St. Olaf College in 1964 and earned his PhD in biochemistry at Stanford Medical School, under Arthur Kornberg. He was a postdoctoral fellow at the Harvard Medical School with Eugene P. Kennedy, who was one of Albert Lehninger's first graduate students. Nelson joined the faculty of the University of Wisconsin-Madison in 1971 and became a full professor of biochemistry in 1982. He was for eight years Director of the Center for Biology Education at the University of Wisconsin-Madison. He became Professor Emeritus in 2013. Michael M. Cox was born in Wilmington, Delaware. After graduating from the University of Delaware in 1974, Cox went to Brandeis University to do his doctoral work with William P. Jencks, and then to Stanford in 1979 for postdoctoral study with I. Robert Lehman. He moved to the University of Wisconsin-Madison in 1983, and became a full professor of biochemistry in 1992. His research focuses on recombinational DNA repair processes. In addition to the work on this text, Cox is a co-author of four editions of Lehninger Principles of Biochemistry. He has received awards for both his teaching and his research, including the 1989 Eli Lilly Award in Biological Chemistry, and two major teaching awards from the University of Wisconsin and the University of Wisconsin System. Hobbies include travel, gardening, wine collecting, and assisting in the design of laboratory buildings.