 He continued his studies at MIT and obtained a Ph.D. in 1973, also in mathematics, under the supervision of Seymour Papert.His doctoral thesis was titled "A Computational Model of Skill Acquisition" focusing on artificial intelligence and machine learning, using a computational performance model named "HACKER".Sussman is a coauthor (with Hal Abelson and his wife Julie Sussman) of the introductory computer science textbook "Structure and Interpretation of Computer Programs".