This paper introduces the LISP programming system, developed by the Artificial Intelligence group at MIT for the IBM 704 computer. LISP was designed to facilitate experiments with a system called the Advice Taker, which could handle declarative and imperative sentences and exhibit "common sense." The system was based on a scheme for representing partial recursive functions of symbolic expressions. The paper describes a formalism for defining functions recursively, which has advantages as both a programming language and a tool for developing a theory of computation. It introduces S-expressions and S-functions, and describes the universal S-function apply, which plays the theoretical role of a universal Turing machine and the practical role of an interpreter. The paper also describes the representation of S-expressions in the IBM 704's memory by list structures and the representation of S-functions by programs. It discusses the main features of the LISP programming system for the IBM 704 and describes another way of describing computations with symbolic expressions. The paper also gives a recursive function interpretation of flow charts. The paper also discusses the representation of S-functions by programs and the status of the LISP programming system in February 1960.This paper introduces the LISP programming system, developed by the Artificial Intelligence group at MIT for the IBM 704 computer. LISP was designed to facilitate experiments with a system called the Advice Taker, which could handle declarative and imperative sentences and exhibit "common sense." The system was based on a scheme for representing partial recursive functions of symbolic expressions. The paper describes a formalism for defining functions recursively, which has advantages as both a programming language and a tool for developing a theory of computation. It introduces S-expressions and S-functions, and describes the universal S-function apply, which plays the theoretical role of a universal Turing machine and the practical role of an interpreter. The paper also describes the representation of S-expressions in the IBM 704's memory by list structures and the representation of S-functions by programs. It discusses the main features of the LISP programming system for the IBM 704 and describes another way of describing computations with symbolic expressions. The paper also gives a recursive function interpretation of flow charts. The paper also discusses the representation of S-functions by programs and the status of the LISP programming system in February 1960.