During the Middle Ages, the Vikings traveled to North America where they studied the forces of disease.

Here, Rudolf Steiner explores this little-known incident and points out the impact that the environment has on human physiology.

He also discusses the birth of modern medicine, the Ahrimanic double and the human organism, the role that wisdom and love play in the spiritual world, the occult brotherhoods with the traditions they maintain for spiritual wisdom, death, and the boundaries of knowledge.