This paper concerns "The Little Red Schoolbook," an English translation of the Danish book "Den lille rode bog fur skoleelever." After the book's publication in the UK, opponents were successful in pressing for its publisher's prosecution. The ensuing trial led to its withdrawal and its bowdlerisation. It is argued that the work played some part in changing social and sexual mores and sex education practice in the UK, being, in effect, the Urtext of the "harm reduction approach". (Contains 7 notes.)