This book is very nuanced. It brings greater depth and clarity to the psychological and spiritual structures of the enneatypes than Riso & Hudson and Palmer & Daniels books - which are more key for understanding what the Enneagram of personality is as a system. This book has influenced my perspective on the similarities between the types based on the interconnectedness and wholeness of the basic needs (passions and fixations) of each type, as well as their essences and virtues. Its a beautiful, complex book, which I will definitely want to refer to often and try to continue to digest.