Year 125 – 1985: Structure and Interpretation of Computer Programs by Harold Abelson and Gerald Jay Sussman, with Julie Sussman | 150 Years in the Stacks

I came across this wonderful quote:

A computer language is not just a way of getting a computer to perform operations but rather … it is a novel formal medium for expressing ideas about methodology. Thus, programs must be written for people to read, and only incidentally for machines to execute.

The source turned out to be this document from 1985.