The Cross and the Pythagorean Decad is a book written by the renowned occultist and philosopher, Helena Petrovna Blavatsky. In this book, Blavatsky explores the significance of the Pythagorean Decad, which is the number ten, in various spiritual and philosophical traditions. She delves into the symbolism of the cross and how it relates to the Pythagorean Decad, as well as its connection to the ancient mystery schools and esoteric teachings. Blavatsky...