In our experience the following books are the best on Christian counseling.
AACC Ethics Book: The Ethical Code of the American Association of Christian Counselors can be downloaded for free at http://www.aacc.net/about-us/code-of-ethics/ .
Faith Therapy: Discusses the need, place, and structure of Christian counseling in the church derived from the Bible and based on the process of salvation by faith, how to overcome self-worth, significance, love and security, and how to treat common problems through faith.
Principles for Life: Teaches 44 biblical p;rinciples and how to use them to construct Christian counseling plans to resolve problems not directly covered in the Bilbe.
Christian Counseling: An overview of Christian counseling.
Competent Christian Counseling: A counseling manual by the president of AACC.
How People Grow: Analysis of the counseling process by the authors of Boundaries.
Effective Biblical Counseling: The classic book on counseling by Dr. Crabb.
Basic Attending Skills: Discusses the basic listening skills. (Secular)
Basic Influencing Skills: A second skills book on basic influencing sikills. (Secular)
DSM IV Made Easy: Includes DSM IV criteria for the diagnostic of mental disorders, clinical cases, and mthods of diagnosis. DSM V will be out in 2013 and will make this book obsolete. (Secular)
Private Practice Made Simple: How to start your private practice. (Secular)
The Clinical Documentation Sourcebook: Forms on CD for your private practice. (Secular)