Knowledge of the Higher Worlds and Its Attainment, by Rudolf Steiner, [1947], at sacred-texts.com

p. vi

Preface to the Edition of May 1918

In working over this new edition I found only minor changes in its substance necessary; but I have added an appendix in which I have endeavored to explain more clearly the psychological foundations to which the disclosures contained in the book must be traced if they are to be accepted without risk of misunderstanding. I believe that the contents of the appendix will also serve to show many an opponent of anthroposophical spiritual science that his judgment is based upon a misconception of the nature of this spiritual science; that he does not see what it really is.

Rudolph Steiner