Humans have evolved three different brain systems for mating and reproduction. While the first is for sex drive, the second is for romantic love and implies tenderness, commitment, passion, desire, giddiness, euphoria, jealousy, and possessiveness towards the partner. The third is attachment, i.e., the sense of security you can feel with a long-term partner. Love is a greater impulse than the sex drive and it is rooted in the most ancient brain areas, alongside the urges of hunger and thirst. As such, love participates in the shaping of human nature and individual identity. In this chapter, I will try to describe this perspective of love, focusing on what happens in the brain and rejecting the romantic picture. When falling in love, you are not only overwhelmed by romantic feelings; you also feel deeply attached to the object of your affection. Moreover, when the reward brain circuit is active, the subject feels a strong motivation to risk everything to win life’s biggest prize: the partner. Finally, it will be argued that love is a kind of addiction able to force people in pathological pathways when other typical circumstances occur.