Alexithymia is a personality trait characterised by difficulty identifying and describing subjective emotional feelings, a restricted imagination, and an externally oriented style of thinking. Individuals with high levels of this trait are at risk of developing several common psychiatric disorders. The concept of alexithymia has evolved considerably over the past twenty years, and this important new work responds to the need for a definitive book on the subject. The research, theory and clinical issues surrounding alexithymia are discussed in depth, examining the psychological, biological and social aspects of the construct and their related outcomes. Featuring contributions from researchers and clinicians in the field of emotion processing and regulation, chapters include methods for assessing and reducing alexithymia, and research findings from diverse fields of scientific enquiry including genetics, neuroimaging studies, emotion regulation, attachment and trauma research, and comorbidities with a number of psychiatric and medical disorders.