The 3-D research was seminal in the fields of computer vision and artificial intelligence. Known as "constraint propagation," the technique is now used in industry for solving problems like route scheduling, package routing and construction scheduling. At M.I.T., Dr. Waltz was taught by Marvin Minsky, a pioneer in artificial intelligence. Dr. Waltz graduated in 1972, then taught computer science at the University of Illinois at Urbana-Champaign and, later, at Brandeis University in Massachusetts. But it was as a member of a group of researchers at the Thinking Machines Corporation, in Cambridge, Mass., that Dr. Waltz made his breakthrough in information retrieval.

"In the early 1970s, he presented a paper in France on buying and selling by computer, what is now called electronic commerce," said Whitfield Diffie, an Internet security expert who worked as a researcher for Dr. McCarthy at the Stanford Artificial Intelligence Laboratory. And in the study of artificial intelligence, "no one is more influential than John," Mr. Diffie said. While teaching mathematics at Dartmouth in 1956, Dr. McCarthy was the principal organizer of the first Dartmouth Conference on Artificial Intelligence. The idea of simulating human intelligence had been discussed for decades, but the term "artificial intelligence" -- originally used to help raise funds to support the conference -- stuck. In 1958, Dr. McCarthy moved to the Massachusetts Institute of Technology, where, with Marvin Minsky, he founded the Artificial Intelligence Laboratory.

George C. Devol, a largely self-taught inventor who drew from science fiction to help develop Unimate, the revolutionary mechanical arm that became a prototype for robots now widely used on automobile assembly lines and in other industries, died on Thursday at his home in Wilton, Conn. In the early 1950s, before the advent of industrial robotics, Mr. Devol (pronounced de-VAHL) built on his own work in electrical engineering and machine controls to design a mechanical arm that could be programmed to repeat precise tasks, like grasping and lifting. He applied for a patent in 1954 and explained the concept to a fellow engineer, Joseph F. Engelberger, at a cocktail party where they discussed their favorite science fiction writers. Mr. Engelberger listened with interest and immediately seized on the significance of the new technology. Mr. Devol named the concept Universal Automation -- later shortened to Unimation -- and received a patent in 1961.

Joseph Weizenbaum, whose famed conversational computer program, Eliza, foreshadowed the potential of artificial intelligence, but who grew skeptical about the potential for technology to improve the human condition, died on March 5 in Gröben, Germany. The cause was complications of cancer, said his daughter Sharon Weizenbaum. Eliza, written while Mr. Weizenbaum was a professor at the Massachusetts Institute of Technology in 1964 and 1965 and named after Eliza Doolittle, who learned proper English in "Pygmalion" and "My Fair Lady," was a groundbreaking experiment in the study of human interaction with machines. The program made it possible for a person typing in plain English at a computer terminal to interact with a machine in a semblance of a normal conversation. To dispense with the need for a large real-world database of information, the software parodied the part of a Rogerian therapist, frequently reframing a client's statements as questions.

Donald Michie, a versatile British scientist and early theorist of artificial intelligence who helped develop a "smart" industrial robot and then applied the technology to diverse fields, died on July 7 in Britain. Dr. Michie (pronounced MICK-ee) died in a car accident near London along with his former wife, Anne McLaren, a biologist and pioneering researcher in the field of reproduction. In the early 1970s, in work that received international attention and helped make Britain a force in advancing artificial intelligence, Dr. Michie led a team that produced "Freddy," a computer-directed robotic arm that could choose and assemble parts from a jumbled and potentially confusing array. To demonstrate Freddy's capabilities, Dr. Michie programmed the machine to put together the parts of a toy truck. Nils J. Nilsson, an emeritus professor of engineering at Stanford University and a former chairman of the department of computer science there, said the machine was "ahead of its time" and impressed researchers at Stanford and elsewhere as "one of the first automatic assembly systems in the world."

Anita Borg, a computer scientist who devoted much of her career to the advancement of women in computer science, died on Sunday at her mother's home in Sonoma, Calif. The cause was brain cancer, said her husband, Winfried Wilcke. Although highly respected as a computer scientist, Dr. Borg made her biggest mark as a champion and mentor of women in what has traditionally been a man's field. Through the several programs she founded, she became virtually synonymous with involving women in the emerging science. In 1987, after returning from a technical conference where she was one of only a handful of women present, Dr. Borg started Systers, an electronic mailing list on technical subjects exclusively for women who are engineers.

Charles A. Rosen, an engineer who was an early researcher in robotic and artificial intelligence and a founder of Ridge Vineyards in Cupertino, Calif., died on Dec. 8 at his home in Atherton, Calif. Born in Montreal, Mr. Rosen came to the United States as a teenager. He studied electrical engineering at Cooper Union in New York City and earned a Ph.D. at Syracuse University. During World War II, he returned to Canada to work on Royal Canadian Air Force aircraft being sent to Britain. After the war, he worked on transistor theory at General Electric Research Laboratories in Schenectady, N.Y., and was the coauthor of an early book on the subject.

Dr. Anne Foerst, 34, a researcher at the Artificial Intelligence Laboratory at the Massachusetts Institute of Technology and the director of M.I.T.'s God and Computers project, apologized on a recent afternoon that a certain robot named Kismet wouldn't be joining our interview. ''Cynthia Breazeal, who built Kismet, is away in Japan right now and there's no getting her going,'' Dr. Foerst said in her German accent, ''but you'd love her. At the Artificial Intelligence Laboratory, engineers are trying to build robots with social skills and humanlike experiences, and so, as an experiment, they've created creatures that they think humans will relate to. Dr. Foerst, a Lutheran minister who supported herself by repairing computers during eight years of higher education in Germany, serves as theological adviser to the scientists building Kismet and the robot's brother, Cog. What exactly do people do here at this laboratory? A. We are trying to build robots that are social and embodied.

Come the summer, many minds will turn to sport as the London Olympics kicks off. So it seems apt that, in a special issue this week, Nature invites its readers to embrace and celebrate a superb marathon runner -- who also happened to be one of the brightest minds of all time. Alan Turing, computer pioneer, wartime code-breaker and polymath, was born in London on 23 June 1912. But for injury, he would probably have joined the British Olympic team for the London games of 1948. Yet, 100 years and one month after his birth, when the Olympics will return to the city, no official celebration of the connection is planned.

In 1955 the computer scientist John McCarthy, who has died aged 84, coined the term artificial intelligence, or AI. His pioneering work in AI – which he defined as "the science and engineering of making intelligent machines" – included organising the first Dartmouth conference on artificial intelligence, and developing the programming language Lisp in 1958. This was the second high-level language, after Fortran, and was based on the radical idea of computing using symbolic expressions rather than numbers. It helped spawn a whole AI industry. McCarthy was also the first to propose a time-sharing model of computing.