This work, though now appearing for the first time in English dress, has not only passed into three editions in Germany, but has been translated into Russian, Swedish, Dutch, Czechish, and Italian, while a French translation is being prepared. It were perhaps well to mention that in this work the words "know" and "knowledge," when used in reference to the supersensible worlds, involve actual experience of them gained by man through his higher organs of perception. The names chosen by the author to describe the higher bodies of man, and other theosophic facts, have been, as far as possible, retained here. Readers will find that they revert with primitive strength to the ancient power of names, and are word pictures and also mnemonics of what they represent. They thus constitute distinct forces too valuable to be withheld from the English reading public.