Although many of the practical activities that arise from Rudolf Steiner's work are well publicized, the philosophy that stands behind them remains largely hidden. Thousands of parents send their children to Steiner and Waldorf schools around the world, while biodynamic farming and anthroposophic medicine are gaining increasing recognition. Yet despite all this and much other visible work, few are aware of the richness of Steiner's spiritual science called "Anthroposophy."

Steiner's original contribution to human knowledge was based on his ability to conduct spiritual research,...