How it Works: The Computer was used by university lecturers to make sure that students started at the same level. Two hundred copies of this same book were ordered by the Ministry of Defence. The MOD wanted the books to be bound in plain brown covers and without any copyright information, to save embarrassing their trainees!

actually, it was printed in the 60s :P

www.theweeweb.co.uk/ladybird/ladybird_history.php
( Azra3l Lubrication Persuasion and Brute Force ™, Tue 12 May 2009, 1:39, archived)