Computer scientist John McCarthy passed away in October 2011. In an SD Times end-of-year retrospective, cryptographer Whitfield Diffie wrote a personal essay focusing on McCarthy’s work on the creation of public-key crypto.

Diffie presented a different side of McCarthy, whom I knew mainly for his pioneering work on artificial intelligence and the LISP programming language. The only time that I recall meeting John McCarthy was at the AAAI conference in 1991, back when I was the editor of AI Expert magazine.

Shortly after our retrospective was published, we received a letter from an irate reader, Peter Schow, who insisted that our tribute was all wrong:

I was stunned to read the John McCarthy tribute in the December 2011 issue of SD Times and not see his foundational contributions to functional programming, Lisp, and artificial intelligence (he invented this phrase!) mentioned at all! His book “LISP 1.5 Programmer’s Manual” (1962) is a classic in Computer Science and is still very relevant today, especially as functional programming is undergoing yet another revival in languages like Scala and Clojure.

The title should have been “Father of Lisp and AI,” but instead the tribute appeared to be hijacked for the purpose of highlighting the author’s public key cryptography invention. It’s mildly disturbing that we are forgetting our history, short as it is, and you owe it to yourself to investigate the subject of John McCarthy’s lecture when he received the 1971 ACM Turing Award. I’m shocked that your editors could have let this been published, and I think you owe your readers a true memorial to John McCarthy.

John McCarthy is a legend—and his work in crypto is no less important than his work in AI. He deserves to be recognized for his contributions in both areas. I’d like to thank Whitfield Diffie and Peter Schow for sharing two views of this incredible man.

(You can read another view in the SD Times obituary of John McCarthy, written by Alex Handy.)

Alan Zeichick is editorial director of SD Times. Read his blog at