What is the historical and evolutionary relationship between human and animal? In this classic text, based on the anthroposophic Spiritual Science, Poppelbaum, a biologist, compares the outer forms of human and animal, revealing the essential differences and contrasting inner experiences. Drawing a bold and clear delineation between the fundamental nature of human beings and that of animals, Poppelbaum tells us that we are not an accidental outcome of animal development, but the hidden source of evolution itself. He discusses the true relationship of both human and animal to their environment and develops a critique of contemporary theories regarding human and animal evolution. He asserts that, rather than a simple reflex of the nervous system, the human spirit is a microcosmic reflection of the spiritual macrocosm, and that our individual consciousness is a crucial seed for future evolution.