John Backus (born December 3, 1924) is an American computer scientist, notable as the inventor of the first high-level programming language (FORTRAN), the Backus-Naur form (BNF, the almost universally used notation to define formal language syntax), and the concept of Function-level programming. He received the 1977 ACM Turing Award for these seminal achievements. Backus' Turing citation read as follows:
- For profound, influential, and lasting contributions to the design of practical high-level programming systems, notably through his work on FORTRAN, and for seminal publication of formal procedures for the specification of programming languages.
Backus was born in Philadelphia, Pennsylvania but grew up in Wilmington, Delaware. He studied at the Hill School in Pottstown, Pennsylvania, and was apparently not a diligent student. After entering the University of Virginia to study chemistry, and failing that, he then joined the US Army and began medical training, which he also dropped out of after nine months.
After moving to New York City he initially took training as a radio technician and discovered an interest in mathematics. He graduated from Columbia University with a degree in the topic in 1949, and joined IBM in 1950. During his first three years, he worked on the SSEC ; his first major project was to write a program to calculate positions of the Moon.
The difficulties of programming were acute, and in 1954 Backus assembled a team to define and develop Fortran for the IBM 704 computer. Whilst arguably not the first high-level programming language, it was the first to achieve wide use. During the latter part of the 1950's Backus served on the international committes which developed ALGOL 58 and the very influential ALGOL 60, which quickly became the de facto worldwide standard for publishing algorithms.
He later worked on a "function-level" programming language known as FP which was described in his Turing Award lecture "Can Programming be Liberated from the von Neumann Style?" Sometimes viewed as Backus's apology for creating Fortran, this paper did less to garner interest in his own FP than to spark research into functional programming in general. FP was strongly inspired by Kenneth E. Iverson's APL, even using a non-standard character set. Backus spent the latter part of his career developing FL (from "Function Level"), a successor to FP. FL was an internal IBM research project and development of the language essentially stopped when the project was finished (only a few papers documenting it remain), but many of the language's innovative, arguably important ideas have now been implemented in Iverson's J and Herrera's NGL programming languages.
Backus was named an IBM Fellow in 1987, and was awarded a Draper Prize in 1993. He retired in 1991.
- Backus' biographies: , , 
- 1977 Turing Award Lecture: Can Programming Be Liberated From the von Neumann Style?
- The FL project