Who is H.P. Blavatsky?
Helena Petrovna Blavatsky was a Russian-born mystic and traveler who wrote the epic books Isis Unveiled in 1877 and The Secret Doctrine in 1888 (among other articles and smaller books). She also co-founded the Theosophical Society in New York City in 1875. Here is a 1991 Russian TV drama/documentary that the Cardiff Theosophical Society in Wales recommends as a good introduction to Blavatsky.