"We are thinking of a renewal of the whole scientific and spiritual worldvew of the present into the near future." (Rudolf Steiner in the public lecture of June 10, 1920 in Stuttgart) This quote sums up the essence of these lectures. From GA 335, these ten lectures were translated from the original German by Hanna von Maltitz who also did the front Cover Illustration. This First Edition English translation has been made available for everyone. The text of both the printed and eBook editions has numerous links to on-line web content that will enhance the reader/researcher in their understanding of the text: search all lectures, read/research the original German texts, compare the English translation to the original German paragraph by paragraph, and explore other related material.