"Secret Doctrine" - the largest and most mysterious of the works of Elena Blavatsky. The purpose of the present work can be defined thus: to prove that Nature is not a "random combination of atoms," and to indicate to man his rightful place in the scheme of the Universe; to save from perversion archaic truths, which are the basis of all religions; to open up to some extent the basic unity from where everyone came; finally, to show that the occult side of nature has never been available to the science of modern civilization.