A scientific trip that is both rigorous and licentious! This disturbing exploration of our "states" shows by example what our emotions owe to the chemistry of the body ... Where have scientific studies of sexuality gotten to? We already knew that seduction is a game that defies all verbal representation. In this area, it is the body that expresses itself above all. However, it is difficult to admit that hormonal secretions play a role in the phenomenon of love at first sight! Psychiatrists, ethologists and biochemists analyze here the intricate relations of amorous feelings and chemical changes in the body. Two hundred and fifty substances come into play at different stages of the process! A clear teaching approach, illustrated, without false modesty, by a couple. From waiting to meet, from desire to weariness.