Ravan San(m)hitha or Kaal Samhita is an ancient book written by Ravana, a demon king who ruled Lanka (now known as Sri Lanka).
Ravan also known as Ravana happens to be the great grandson of the god of creations – Lord Brahma. His mother Kaikashi was an exponent of demon magic and tantras and his father Vishravas a devotee of Lord Shiva. Hence, Ravana by virtue became an ardent devotee of Lord Shiva well-versed in Upanishads, Vedas, Karmas and Mantras along with magical prowess during his growing years itself. Fuelled by his aggressive spirit and strong determination he went on to practice even difficult pooja forms to become a formidable king. He did penance for years together with a pure heart to win the hearts of Lord Brahma and Lord Shiva and got powers in turn for his great devotion to have control over Devtas, Gandharvas, Ashta Digpals and even the Navagrahas.
Narrated in an old cryptic method, Ravan san(m)hita offers immense wisdom on the ways to control future and even death. If learnt accurately, one would be able to become a vedic scholar mastering the Pooja methods, ayurveda and astrology to achieve sound health and wealth. In short you could become powerful enough to convert your desire into reality.