The Jewel of Annual Astrology is an encyclopaedic treatise on Tājika or Sanskritized Perso-Arabic astrology, dealing particularly with the casting and interpretation of anniversary horoscopes. Authored in 1649 CE by Balabhadra Daivajña, court astrologer to Shāh Shujāʿ – governor of Bengal and second son of the Mughal emperor Shāh Jahān – it casts light on the historical development of the Tājika school by extensive quotations from earlier works spanning five centuries.

With this first-ever scholarly edition and translation of a Tājika text, Martin Gansten makes a significant contribution not only to the study of an important but little known knowledge tradition, but also to the intellectual historiography of Asia and the transmission of horoscopic astrology in the medieval and early modern periods.