John Backus was an American computer scientist best known for leading the team that developed FORTRAN, the first widely used high-level programming language. His work revolutionized computer programming, making it more accessible and efficient. Backus also contributed to the development of Backus-Naur Form (BNF), a notation used to describe the syntax of programming languages. His contributions to computer science have had a profound and lasting impact on the field, shaping the way software is developed and used today.