This eBook edition of "The Secret Doctrine" has been formatted to the highest digital standards and adjusted for readability on all devices. The Secret Doctrine is one of the most influential esoteric and occult books of all time. In the first part of the book the author explains the origin and evolution of the universe itself, in terms derived from the Hindu concept of cyclical development. While in the second part she describes the origins of humanity through an account of "Root Races" said to date back millions of years.