This compilation of articles written by the editors of Scientific American explores the complicated subject of identity from a scientific perspective. What determines which traits, qualities, and beliefs a person will possess or be drawn to in other people? Researchers have examined genetic makeup, brain activity, emotional responses, and social structures to find patterns that can help explain how identity is formed. Science can be used to explain stereotyping, gender and sexuality, our tastes and beliefs, and the factors that shape our personalities.