LaHaye gives a clear analysis of personalities both with and without the influence of the indwelling gift of the Holy Spirit. To do so he utilizes the ancient four temperaments: Sanguine, Choleric, Melancholy, and Phlegmatic. Though some would find this system archaic, LaHaye makes a clear and reasonable defense for this choice.
While this book is certainly of clinical interest for the counseling professional or student, the writing is engaging and clear enough for a layperson. I would recommend this as a beneficial resource for anyone interested in a uniquely Christian perspective on drives the actions and style of people - themselves or others. It may also serve as barometer of personal Spiritual maturity.