Rudolf Steiner's core mission, repeatedly delayed due to the incapacity of colleagues, was to pursue contemporary spiritual-scientific research into the phenomena of reincarnation and karma. This stimulating book describes the winding biographical path this mission took, and in particular focuses on the mystery of Rudolf Steiner's connection with the influential medieval philosopher and theologian, Thomas Aquinas. Utilizing numerous archival sources and publications, Thomas Meyer reveals many facts relating to Steiner's core mission, and shows the critical roles played by Wilhelm Anton Neumann and Karl Julius Schroer in its genesis and development. Meyer examines how Steiner's pupils responded to his insights into karma, and places this 'most intrinsic mission' into the context of current divisions within the anthroposophic movement. In particular, he highlights the place of spiritual science within culture and history, showing how Steiner developed the great scientific ideas of evolution propounded by Darwin by raising them to the plane of each individual's soul and spiritual development. As Steiner stated in 1903: 'Scientific researchers explain the skull forms of higher animals as a transformation of a lower type of skull. In the same way one should explain a soul's biography through the soul biography which the former evolved from.'