Jyotish is the ancient science of deciphering the essential uniformity of principles that guide the celestial bodies and the events in the world. Because of these unified principles, what happens in this world can be deciphered from what happens in the heavenly world. The movement of Grahas or Grahas, as they are called in Sanskrit, provides a unified language used for deciphering the occurrences of this world, including the matters concerning humans, animals, plants, weather and nations. This is an exciting subject of associating the symbols of nature with the occurrences of mundane events or human affairs; however, it is exceedingly vast. To cover the expansive vistas of this subject, one must undertake a structured approach, which covers several areas of Jyotish, including Ganita, Samhita and Hora. The Ganita deals with the mathematical or astronomical aspect of this subject, the Samhita deals with the mundane elements such as weather forecasting, earthquakes, rainfall etc. , and the Hora deals with the judgement of the Kundalis of individuals. This book introduces the subject.