There are millions of publications on well-being, but most focus on one component of well-being, one factor influencing well-being, or the well-being of one group in one culture. The present book provides an overview of well-being, integrating many factors influencing the well-being of many groups in many cultures and over time. Well-being has many components, including thoughts, feelings, and behaviors. Positive emotions indicate that needs are being met, while negative emotions indicate that needs are not being met, or are perceived as being threatened in some manner. Meeting physical, emotional, and cognitive needs frequently involves interacting with others, in single encounters, repeated encounters, or ongoing relationships. The book compares the well-being of various types of romantic partners and singles across time and across cultures.