On the Enigmas of the Soul (Basic Anthroposophy)

This book is the first place Steiner mentions the threefold mapping of human thinking, feeling, and willing onto the nervous and sensory system, the rhythmic system, and the metabolic/limb system. This tripartition then becomes central to Steiner's later development of Waldorf education and the so-called Threefold Social Order. It also features a long obituary celebrating Franz Brentano, who was Steiner's teacher and a co-founder of the phenomenological movement in philosophy.