For anyone who was interested in relationships and sex in the early 1970s, the appeareance of The Joy of Sex in 1972 was a landmark. Written by the infamous Alex Comfort, it was the first illustrated sex manual to celebrate in words and pictures the rich variety of sensual intimacy.

It was decided early on to use illustrations rather than photographs so as not to fall foul of obscenity laws. Only the previous summer Britain had witnessed the media frenzy of the Oz trials, in which the editors of a satirical magazine were found guilty of obscenity for publishing a sexualised parody of the well-known children’s character Rupert Bear.

There were originally two illustrators working on The Joy of Sex – Charles Raymond did the colour drawings of a couple making love, while Chris Foss drew the more technical black-and-white illustrations of positions and techniques.

The original plan was to take photographs of models working in the sex industry and use them as the basis for copied drawings, but when budget problems arose Charles Raymond came to the rescue, volunteering to model with his German wife, Edeltraud. The couple later recalled it as extremely hard work, particularly since the strikes and power cuts of that year meant the lights could go out at any moment.

Despite being banned in many countries, including Ireland, and booksellers and librarians refusing to stock it in many states in the USA, the book sold more than ten million copies.

What happened subsequently to Charles and Edeltraud we have not been able to discover, but they were instrumental in helping many 1970s couples enjoy their sexuality.