Biblical Psychology, written by P. Thomas Schaller, is a textbook for the class of the same name at Maryland Bible College and Seminary. Though it is intended to supplement the Biblical Psychology class at MBC&S it is also suited for personal study.
An excerpt from the book's introduction:
The word "psychology" comes from two Greek words, psyche, meaning "soul," and logia, meaning "words" or "discourses." It is science of the soul and and its study addresses the nature of man. Man has always been fascinated by his soul. He has studied man's behavior and devised various theories concerning the internal working of the soul. But the only true psychology is a Bible-based psychology. The only true psychology is a psychology where the Creator tells the creation how He made him.