This paper is an introduction to the main features of ALGOL 68, emphasizing the novel features not found in many other programming languages. The topics, data types (modes), type conversion (coercion), generalized expressions (units), procedures, operators, the standard prelude, and input/output, form the basis of the paper. The approach is informal, relying heavily on many short examples. The paper applies to the Revised Report, published in 1975, rather than to the original report, published in 1969. © 1976, ACM. All rights reserved.