Sussman is a coauthor (with
Hal Abelson and
Julie Sussman) of the introductory computer science textbook
Structure and Interpretation of Computer Programs (SICP). It was used at MIT for several decades, and has been translated into several languages. Sussman's contributions to
artificial intelligence include problem solving by debugging almost-right plans, propagation of constraints applied to electrical circuit analysis and synthesis, dependency-based explanation and dependency-based backtracking, and various language structures for expressing problem-solving strategies. Sussman and his former student,
Guy L. Steele Jr., invented the programming language
Scheme in 1975. Sussman saw that artificial intelligence ideas can be applied to
computer-aided design (CAD). Sussman developed, with his graduate students, sophisticated computer-aided design tools for
Very Large Scale Integration (VLSI). Steele made the first Scheme hardware chips in 1978. These ideas and the AI-based CAD technology to support them were further developed in the Scheme chips of 1979 and 1981. The technique and experience developed were then used to design other special-purpose computers. Sussman was the principal designer of the
Digital Orrery, a machine designed to do high-precision integrations for
orbital mechanics experiments. The Orrery hardware was designed and built by a few people in a few months. Using the Digital Orrery, Sussman has worked with
Jack Wisdom to discover numerical evidence for
chaotic motions in the outer planets. The Digital Orrery machine is now retired at the
Smithsonian Institution in Washington, DC. Sussman was also the lead designer of the Supercomputer Toolkit, another
multiprocessor computer optimized for evolving of
ordinary differential equations. The Supercomputer Toolkit was used by Sussman and Wisdom to confirm and extend the discoveries made with the Digital Orrery to include the entire planetary system. Sussman has pioneered the use of computational descriptions to communicate methodological ideas in teaching subjects in Electrical Circuits and in Signals and Systems. Over the past decade Sussman and Wisdom have developed a subject that uses computational techniques to communicate a deeper understanding of advanced
classical mechanics. In
Computer Science: Reflections on the Field, Reflections from the Field, he writes "... computational algorithms are used to express the methods used in the analysis of dynamical phenomena. Expressing the methods in a computer language forces them to be unambiguous and computationally effective. Students are expected to read the programs and to extend them and to write new ones. The task of formulating a method as a computer-executable program and debugging that program is a powerful exercise in the learning process. Also, once formalized procedurally, a mathematical idea becomes a tool that can be used directly to compute results." Sussman and Wisdom, with Meinhard Mayer, have produced a textbook,
Structure and Interpretation of Classical Mechanics (SICM), to capture these new ideas. Sussman and Abelson have also been a part of the
free software movement, including releasing
MIT/GNU Scheme as
free software and serving on the board of directors of the
Free Software Foundation. In 2011, Sussman attended an event in the
Virgin Islands, known as the "Mindshift Conference", hosted by
Jeffrey Epstein and
Al Seckel. Sussman later confirmed that he attended the conference and stated that he learned about the sexual abuse allegations against Epstein only after the conference took place, but declined to comment publicly on his relationship with Seckel. Sussman's work is presented in many videos, such as: with Hal Abelson in a full 20-lecture version of MIT's SICP course, for LispNYC, at the International Conference on Complex Systems, for
ArsDigita University, and giving the keynote talk at a Strange Loop conference. ==Awards and organizations==