May 1959
First working Lisp interpreter
By May 1959, John McCarthy's Lisp interpreter at MITMassachusetts Institute of Technology — a research university central to many computing breakthroughs. was working well enough for real research on the IBMInternational Business Machines — a major computer and enterprise technology company since the early 20th century. 704.
What it was for
Lisp treated programs as data you could manipulate — built for AI and symbolic work like theorem proving and language experiments. It later influenced Emacs, CAD tools, and languages from PythonA high-level language known for readability — dominant in data science, scripting, and web backends. to Clojure.
Why it's here
Lisp introduced a new way to write programs as nested lists — ideas that later shaped AI tools, text editors, and functional programmingA style emphasizing functions and immutable data over step-by-step state changes — influences Haskell, Lisp, and modern languages..
Why it mattered
It proved that treating code like data could power real research tools, not just theory.
What it solved
Researchers working on reasoningStep-by-step logical thinking in AI models — chain-of-thought before answering hard problems. and AI needed a language for symbols and logic, not just the number-crunching style of FORTRAN.
Media
ImageLisp (programming language)"null0", CC BY-SA 2.0, via Wikimedia Commons