Whoever is familiar with the essence of “proof”, it is clear that the human soul finds the truth differently, not through the paths of argument, struggle against each other. And in accordance with these views and views, let this book appear in its second edition before modern times.

"This book gives a description of certain areas of the supersensible world. Anyone who wants to recognize only the sensory world can consider this description as a non-existent creation of fantasy. But anyone who wants to look for paths leading beyond the limits of the sensory world will soon learn to understand that human life acquires value and meaning only through the insight of other worlds." Translation of the second German revised and expanded edition of 1908.