David Leigh Waltz (28 May 1943 – 22 March 2012) was a computer scientist who made significant contributions in several areas of artificial intelligence, including constraint satisfaction, case-based reasoning and the application of massively parallel computation to AI problems. He held positions in academia and industry and at the time of his death, was a professor of Computer Science at Columbia University where he directed the Center for Computational Learning Systems. Education Waltz was born in Boston, Massachusetts in 1943. He attended the Massachusetts Institute of Technology (MIT) where, as a student of artificial intelligence pioneer Marvin Minsky, he was part of the MIT Artificial Intelligence Laboratory and received S.B. (1965), M.S. (1968) and Ph.D. (1972) degrees, all in Electrical Engineering. His Ph.D. dissertation on computer vision initiated the field of constraint propagation, which allowed a computer program to generate a detailed three-dimensional view of an object given a two dimensional drawing with shadows. Career Following his graduate work at MIT in 1972, Waltz became a professor of computer science at the University of Illinois at Urbana-Champaign. In 1984 he joined Thinking Machines Corporation where he led the Knowledge Representation and Natural Language (KRNL) group. There, his access to massively parallel supercomputers enabled him to work on new methods for information retrieval involving comparisons to large amounts of data. With Craig Stanfill, he originated the field of memory-based reasoning branch of case-based reasoning. His research interests also included massively parallel information retrieval, data mining, learning and automatic classification with applications protein structure prediction, and natural language processing and machine learning applications applied to the electric power grid. While at Thinking Machines, Waltz was also a Professor of Computer Science at Brandeis University. In 1993 Waltz left Thinking Machines to join NEC Research Institute in Princeton, where he eventually rose to become President of NEC Research. Waltz joined Columbia University in 2003 as the Director of the Center for Computational Learning Systems. Waltz served as president of the Association for the Advancement of Artificial Intelligence (AAAI) from 1997 to 1999 and is the former Chairman of the Association for Computing Machinery (ACM) Special Interest Group on Artificial Intelligence (SIGART). He was on the Advisory Board for IEEE Intelligent Systems, and the board of the Computing Community Consortium of the Computing Research Association, and National Science Foundation (NSF) Computer Science Advisory Board. He was on the Army Research Lab Technical Advisory Board