Rudolf Steiner 
Theosophy (Translated) 
Introduction to the supersensible knowledge of the world and human destiny

In this book we want to give a description of some parts of the supersensible world. Whoever wants to admit only the sensory world will consider this description a vacuous product of the imagination. But whoever wishes to seek the paths that lead out of the world of the senses will soon come to understand that human life acquires value and meaning only if one penetrates with one's eyes into another world. This penetration does not distract man, as many fear, from "real" life. It is only in this way that he learns to stand firm and secure in life. He learns to know its causes, while, if he ignores them, he gropes like a blind man through its effects. Only through knowledge of the supersensible world does the sensible "reality" acquire meaning. Therefore, this knowledge increases, not diminishes, our capacity for life. Only he who understands life can become a truly "practical" man.