of California at Irvine, Joe Stoy at Oxford, Elisha Sacks at Purdue, and Jan Komorowski at the Norwegian University of Science and Technol- ogy. We are exceptionally proud of our colleagues who have received major teaching awards for their adaptations of this subject at other uni- versities, including Kenneth Yip at Yale, Brian Harvey at the University of California at Berkeley, and Dan Huenlocher at Cornell. Al Moyé arranged for us to teach this material to engineers at Hewle- Packard, and for the production of videotapes of these lectures. We would like to thank the talented instructors—in particular Jim Miller, Bill Siebert, and Mike Eisenberg—who have designed continuing edu- cation courses incorporating these tapes and taught them at universities and industry all over the world. Many educators in other countries have put in significant work translating the first edition. Michel Briand, Pierre Chamard, and An- dré Pic produced a French edition Susanne Daniels-Herold produced a German edition and Fumio Motoyoshi produced a Japanese edition. We do not know who produced the Chinese edition, but we consider it an honor to have been selected as the subject of an “unauthorized” translation. It is hard to enumerate all the people who have made technical con- tributions to the development of the Scheme systems we use for in- structional purposes. In addition to Guy Steele, principal wizards have included Chris Hanson, Joe Bowbeer, Jim Miller, Guillermo Rozas, and Stephen Adams. Others who have put in significant time are Richard Stallman, Alan Bawden, Kent Pitman, Jon Ta, Neil Mayle, John Lamp- ing, Gwyn Osnos, Tracy Larrabee, George Carree, Soma Chaudhuri, Bill Chiarchiaro, Steven Kirsch, Leigh Klotz, Wayne Noss, Todd Cass, Patrick O’Donnell, Kevin eobald, Daniel Weise, Kenneth Sinclair, An- thony Courtemanche, Henry M. Wu, Andrew Berlin, and Ruth Shyu. xxvii