Abelson has a longstanding interest in using computation as a conceptual framework in teaching. He directed the first implementation of Logo for the Apple II, which made the language widely available on personal computers beginning in 1981; and published a widely selling book on Logo in 1982. His book "Turtle Geometry," written with Andrea diSessa in 1981, presented a computational approach to geometry has been cited as "the first step in a revolutionary change in the entire teaching/learning process."
Together with Gerald Sussman, Abelson developed MIT's introductory computer science subject, "Structure and Interpretation of Computer Programs," a subject organized around the notion that a computer language is primarily a formal medium for expressing ideas about methodology, rather than just a way to get a computer to perform operations. This work, through Abelson and Sussman's popular computer science textbook, videotapes of their lectures, and the availability on personal computers of the Scheme dialect of Lisp (used in teaching the course), has had a world-wide impact on university computer-science education.
Abelson and Sussman also cooperate in codirecting the MIT Project on Mathematics and Computation, a joint project of the MIT Artificial Intelligence Laboratory and the MIT Laboratory for Computer Science, whose goal is to create better computational tools for scientists and engineers. But even with powerful numerical computers, exploring complex physical systems still requires substantial human effort and human judgement to prepare simulations and to interpret numerical results. Together their students, Abelson and Sussman are combining techniques from numerical computing, symbolic algebra, and heuristic programming to develop programs that not only perform massive numerical computations, but that also interpret these computations and "discuss" the results in qualitative terms. Programs such as these could form the basis for intelligent scientific instruments that monitor physical systems based upon high-level behavioral descriptions. More generally, they could lead to a new generation of computational tools that can autonomously explore complex physical systems, and which will play an important part in the future practice of science and engineering. At the same time, these programs incorporate computational formulations of scientific knowledge that can form the foundations of better ways to teach science and engineering.
Miscellaneous
Richard Stallman apparently enjoys sleeping on Dr. Abelson's couch.
Also, Dr. Abelson is known to have been involved in the publishing of Andrew Huang's "Hacking the X-Box", Keith Winstein's 7 line Perl DeCSS script, and MIT's campus wide cable music distribution system.
Hal Abelson is credited with the following quip, which may be the greatest one-liner in the history of science:
"If I have not seen as far as others, it is because there were giants standing on my shoulders." --Hal Abelson