Kissing is a symbol of desire, romance, love and affection.
An accepted greeting between friends and family, it plays a role throughout our lives from cradle to grave.
The origins of this bizarre custom, however, are still something of a mystery to scientists.
In this intriguing, informative and entertaining journey beyond the lips, Dr Gillian Rice investigates the theories about the origins of the kiss, and the sexual chemistry, physiology and cultural significance of this most powerful symbol of trust or betrayal.
After all a kiss, is anything but just a kiss; it's a unique form of communication.
We are people of lips - something that sets us apart from almost all other life - and our lips are everted, making them the most exposed erogenous zone of our body.
The area of the brain stimulated by a brush against the lips, is larger than that concerned with the entire reproductive organs! As to its origin, some anthropologists believe that kissing evolved from sniffing.
Some indigenous cultures do rub noses rather than kissing.
It is a primal urge to sample another persons scent, and test their sexual chemistry.
An alternatively view is that kissing may evolved from 'kiss feeding', in which mothers masticate food before passing it on to a baby.
The programme also explores the role of the lips when it comes to attraction.
Over 34 facial muscles are involved in making a pout, and, for most of us, the first romantic kiss is an unforgettable experience.
But is all this kissing good for you? Well over 5 million bacteria are exchanged between you and your partner in one long, lingering passionate kiss.