The experience of emotion is a core element of human psychology, and the capacity to recognize emotions in others is an essential component of human social life. In some individuals, the ability to understand emotion in oneself and in others is compromised due to psychiatric disorders, which can have a substantial deleterious effect on one's sense of well-being. This field has also been explored in the context of computer science, as artificial intelligence centered around emotion recognition has the potential to transform the nature of human-machine interaction. This book consists of three chapters that explore these concepts, granting students and researchers new insight on the nature of this necessary element of human life.