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

With this first-ever scholarly edition and translation of a Tajika 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.