Sussman is a coauthor (with Hal Abelson and Julie Sussman) of the introductory computer science textbook used at M.I.T. The textbook, "Structure and Interpretation of Computer Programs," has been translated into French, German, Chinese, Polish, and Japanese. As a result of this and other contributions to computer-science education, Sussman received the ACM's Karl Karlstrom Outstanding Educator Award in 1990, and the Amar G. Bose award for teaching in 1992.
Sussman's contributions to Artificial Intelligence include problem solving by debugging almost-right plans and various language structures for expressing problem-solving strategies. His work with Richard Stallman developed propagation of constraints for application to electrical circuit analysis and synthesis, and dependency-based explanation and backtracking. Sussman and his former student, Guy L. Steele Jr., invented the Scheme programming language in 1975.
Sussman saw that Artificial Intelligence ideas can be applied to computer-aided design. Sussman developed, with his graduate students, sophisticated computer-aided design tools for VLSI. Steele made the first Scheme 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 was 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 was designed and built by a few people in a few months, using AI-based simulation and compilation tools.
Using the Digital Orrery, Sussman has worked with Jack Wisdom to discover numerical evidence for chaotic motions in the outer planets. The Digital Orrery 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 systems 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. 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 our 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," to capture these ideas.
Sussman has been involved in the engineering of both amateur and professional telescopes. He redesigned and rebuilt the mirror-support system for the 2.4m Hiltner telescope on Kitt Peak, and he helped build and, with Julie Sussman, wrote the first prototype software for the guider-probe controllers for the 6.5m Magellan telescopes on Las Campanas in Chile.
Sussman is a fellow of the Institute of Electrical and Electronics Engineers (IEEE). He is a member of the National Academy of Engineering (NAE), a fellow of the American Association for the Advancement of Science (AAAS), a fellow of the Association for the Advancement of Artificial Intelligence (AAAI), a fellow of the Association for Computing Machinery (ACM), a fellow of the American Academy of Arts and Sciences, and a fellow of the New York Academy of Sciences (NYAS). Sussman is a founding director of the Free Software Foundation. He has been a bonded locksmith. He is a life member of the American Watchmakers-Clockmakers Institute (AWI), a member of the Massachusetts Watchmakers-Clockmakers Association, a member of the Amateur Telescope Makers of Boston (ATMOB), and a member of the American Radio Relay League (ARRL).