The Psychology of Self-Esteem is a book by Nathaniel Branden, first published in 1969. It explains Branden's theories of human psychology, focusing on the role of self-esteem. Most of the book was written during Branden's association with Ayn Rand, and it reflects some of her philosophical ideas. The book's success helped to popularize the idea of self-esteem as an important element of self-improvement. Source: Wikipedia (en)