The material here presented by Laurie Beth Jones is excellent and provides tremendous insight for personality studies. Unlike other personality profile models which possess types difficult to grasp and to inter-relate, this model provides the user with common elements which are easy to understand and simple to intertwine. For example, we all understand the nature of fire, and we all understand the result of fire and water being mixed together. Other personality profiles models fall far short of this one.The only reason I didn't give this book five stars is that the style is too "earthy." Being a fire/wind myself, I found it cumbersome to wade through all the detailed explanations and examples. Overall however, it is a great volume -- I recommend it!