Sefer Yetzirah is one of the oldest Jewish esoteric texts, which inspired mystics throughout the centuries, and it is hard to exaggerate its importance in the development of spiritual thought. In a concise style it describes the Divine Primordial Creation of the World --the Ten Sefirot, Physical Space, Calendric Time, the Human Body and Life Conditions-- by combining the primary Elements of Air, Fire and Water, with the creative power of Numbers and the 22 Letters of the Hebrew Alphabet as the Prima Materia.