Love, one of the most profound of human emotions, love that accompanies us from puberty to old age, love that follows us from ancient times to modern, from ancient writings, through the Bible and the texts of medieval scribes to modern day books and movies. Through the millennia love has lost none of its secrecy, charm, attractiveness, craziness, even in this digital age, when we are overwhelmed by information.

But what is love? Where does this emotion originate? Are we humans the only living beings feeling this emotion? Can love be explained by some chemical reactions in our brains?...