After growing up in New York, Neumann earned three degrees from Harvard: a Bachelor’s in Mathematics in 1955 — during which time Albert Einstein took two hours to have breakfast with him, to discuss simplicity in design, and then a Masters (1955) and Ph.D (1961) in Applied Mathematics and Science. In between the latter two he studied in Germany on a Fulbright scholarship. In short, Neumann had a brilliant mind.
So much so that at Harvard, Neumann was greatly trusted by the designer of the Mark IV computer, Howard Aiken, who let Neumann use the Mark IV whenever he wanted — at least when it wasn’t in demand by its primary users. “I was the operator, maintainer and guru,” Neumann said, and used the Mark IV to help prepare his undergraduate thesis, on computing elliptic integrals, taking over the computer from its weekday operators each Friday at 5:00 p.m., and not leaving until 8:00 a.m. Monday morning. Neumann and some other students, most notably Fred Brooks, used the Mark IV for some of the earliest work in computer music. Steven Levy’s book Hackers: Heroes of the Computer Revolution * described some of the earliest hackers at MIT in the early 1960s. Yet Neumann was doing this in 1954. Was he, then, the first such hacker? Hard to say for sure, but he was certainly one of the first.
Not surprisingly, Neumann was snapped up by AT&T’s Bell Labs, working there from 1960 to 1970, where he worked on the Multics (“Multiplexed Information and Computing Service”) time-shared operating system, which “has influenced all modern operating systems since, from microcomputers to mainframes” even though it essentially failed when GE decided to get out of the computer business. Most notably, it influenced the design of Unix, which was originally written by two Multics programmers, Ken Thompson and Dennis Ritchie. Unix was originally named Unics, a pun on Multics.
(Aside: Simson Garfinkel and Harold Abelson write in Architects of the Information Society: Thirty-Five Years of the Laboratory for Computer Science at MIT that Unics/Unix was named when Neumann, watching a demo of the new OS, suggested it be named UNICS, pronounced “eunuchs” as it was a “castrated Multics”. Dennis Ritchie denies the story is true.)
In 1971, Neumann went to California to work at the Stanford Research Institute (now SRI International) in Menlo Park. He worked on another OS, PSOS: the Provably Secure Operating System from 1973 to 1980, helping to establish his expertise in computer security. In the early 1980s, he worked with information security researcher Dorothy Denning; both were becoming recognized experts in the field, and their findings, published in 1985, are still the basis for computer intrusion detection systems today.
In February 1985, working closely with the Association for Computing Machinery, Neumann read a call by Adele Goldberg, ACM’s president, who wrote that “the ACM Council passed an important resolution [which begins]: ‘Contrary to the myth that computer systems are infallible, in fact computer systems can and do fail. Consequently, the reliability of computer-based systems cannot be taken for granted. This reality applies to all computer-based systems, but it is especially critical for systems whose failure would result in extreme risk to the public. Increasingly, human lives depend upon the reliable operation of systems such as air traffic and high-speed ground transportation control systems, military weapons delivery and defense systems, and health care delivery and diagnostic systems.’”
Therefore, Goldberg called for “a forum on risks to the public in the use of computer systems,” Neumann wrote, and he answered that call by creating the email publication Risks Digest, issuing the first issue on Thursday, 1 August 1985, with himself as editor, noted with his usual “PGN” initials on many of the items. I’ve been a subscriber on and off since the late 1990s, and the last issue I received came out on 12 April 2026 and noted near the top, “Peter G. Neumann, founder and still moderator”. It was still being read, the New York Times says, by “hundreds of thousands” of computer security research, systems administrators, and regular people with an interest in the topic.
Neumann never retired: he was still working for SRI on advanced computer security designs, and in the same office he was given in 1971. “There’s no limit on the impact that a small team can have if they don’t care who gets credit,” said Patrick Lincoln of DARPA’s Information Innovation Office, who adds that Neumann often helped behind the scenes without asking for credit. “I’m fundamentally an optimist with regard to what we can do with research,” Neumann once said. “I’m fundamentally a pessimist with respect to what corporations who are fundamentally beholden to their stockholders do, because they’re always working on short-term appearance.” Dr. Peter Gabriel Neumann died on May 17, after a fall. He was 93.