An integrated approach to the psychology of underachievement, unifying theory and practice. Examines different types of underachievers, explores the relationship between personality and underachievement, and provides useful guidelines for clinical practice. Provides an outline and summary of the voluminous (and often contradictory) literature, then presents theoretical models of the underachiever that are grounded in mainstream diagnostic and therapeutic theory. Offers examples of each personality type, so practitioners can easily recognize and treat them.