What was the name of the manual written by Alan Turing for the Manchester Mark I?

The manual Alan Turing wrote was the “Programmers' Handbook for Manchester Electronic Computer.”

Written around 1950, it was an early programming guide for the Manchester computing project and its commercial development. The machine described was closely connected with the Ferranti Mark 1, the commercial successor derived from the university’s Manchester Mark 1 design.

The handbook explained how to program the machine in raw machine code. Programmers used a modified five-bit character system, rather than a modern assembly language, to represent instructions and data on punched paper tape. Turing also developed the Scheme A method for organising programs and routines.

A common mix-up is to call this an operating manual or a user guide. Those descriptions miss its main purpose: it was a programmer’s handbook. Later editions and related documents used titles referring to the Manchester Electronic Computer Mark II, while the first edition is generally associated with Turing and the early Ferranti machine. The Manchester Mark 1 itself was operational by 1949 and helped pioneer practical stored-program computing.