Roy F. Baumeister 
Self-Esteem [PDF ebook] 
The Puzzle of Low Self-Regard

Summarizing and integrating the major empirical research of the past twenty years, this volume presents a thorough review of the subject, with a special focus on what sets people with low self-esteem apart from others. As the subject is central to the understanding of personality, mental health, and social adjustment, this work will be appreciated by professionals and advanced students in the fields of personality, social, clinical, and organizational psychology.