JOY OF SEX UPDATED ED - Tapa dura

At first I was overawed - how could I rewrite the most famous sex book in the world? I remember the first edition in 1972, and I knew that The Joy of Sex has not only reflected but also created huge changes in our attitudes to passion.

But then I realised that Dr Comfort and I have the same values and aims. We both believe that sex is hugely important in life - it keeps us healthy, sane and long-lived. We both believe that people have the right to a good sex - and that with today's pressures there's even more need for a book that encourages us to relax, to play and to really enjoy passion. But we both also believe that sex is not just a game - it's a hugely powerful force in life and needs to be taken seriously.

How have I reinvented the original book? First I needed to update the science. Research has moved on since 1972 and we now know much more about the human body, the sexual process - and how to solve sexual problems and enhance sexual enjoyment.

I've also needed to change the book to reflect social shifts. Compared to 1972, society's much more relaxed about sexuality; many more of us have sex, have sex outside marriage, and have sex with a variety of people in a variety of ways. But in some ways we're now more aware of the problems sex can bring with it - unwanted pregnancy, sexually transmitted infections and the pain of infidelity and rejection.

So along with all the best bits of the original book - which cover everything from breasts to bondage, orgasm to orgies - I've not only included new sections on physiological elements like hormones, aphrodisiacs and the clitoris. I've not only introduced coverage of new developments in sexuality such as the internet, sex shops, sex toys, and new techniques like the CAT position and the Venus Butterfly. I've also written about love and compatibility, seduction and fidelity, sexual confidence and keeping desire alive.

It's taken me two years to complete this project and they've been two of the most fascinating years of my life. I've constantly been amazed at how much there is to know about sex nowadays, and how much there is to appreciate.

I really hope that everyone who reads this takes away the same message. We all deserve a rich sex life. We all deserve the joy of sex.