Nadi astrology, or Nāḍi Jyotiṣa, is a very ancient and very mystical branch of astrology only practiced in the Tamil Nadu state of India. Unlike regular date-of-birth and time-of-birth horoscopes, Nadi astrology uses your thumb impression to locate a palm leaf—namely, one containing your entire life's plan, written thousands of years ago by ancient rishis or sages.
These leaves, conserved in libraries or "nadi granthas," contain ancient Tamil script inscribed on dry palm leaves and have endured centuries of rigorous conservation.