Jeffrey D. Ullman is the Stanford W. Ascherman Professor of Computer Science (emeritus) at Stanford University. He is the author or co-author of 16 books, including Elements of ML Programming. His research interests include data mining, information integration, and electronic education. He is a member of the National Academy of Engineering, and recipient of a Guggenheim Fellowship, the Karl V. Karlstom Outstanding Educator Award, the SIGMOD Contributions and Edgar F. Codd Innovations Awards, and the Knuth Prize. Jennifer Widom is Professor of Computer Science and Electrical Engineering at Stanford University. Her research interests span many aspects of nontraditional data management. She is an ACM Fellow and a member of the National Academy of Engineering, she received the ACM SIGMOD Edgar F. Codd Innovations award in 2007 and was a Guggenheim Fellow in 2000, and she has served on a variety of program committees, advisory boards, and editorial boards.