Every individual's personality is unique. Personality is a combination of biological temperament, willingness to explore and socialise, intelligence, education and accumulated experience in reaction to life events. Some personalities are so different from others that they are sometimes called personality disorders. The behaviour or people with such extreme personalities may lead to them harming themselves or harming others. This chapter explores case histories based on personality. If you listen to mothers describing their children they will often tell you how each pregnancy had its own characteristics and how even at birth each child differed in some way from its siblings. Some babies seem to be very active in the womb and to react to their mother's behaviour and others seem relatively inactive. At birth some babies are relatively alert and excitable and others are more stolid and slow to react. The newborn baby and his or her mother react and adapt to each other.