The Siddhantasiroma?i was composed in 1150 CE by the celebrated mathematician–astronomer Bhaskaracarya. In the Grahaga?itadhyaya part of it, most of the standard calculations and algorithms in Indian astronomy of his times are included. All these are explained in detail with commentary on the text, namely, the Vasanabha?ya or Mitak?ara. This book is on this part only. All the 460 verses of this part have been translated afresh in this work. Now, it is in the Vasanabha?ya that the contents of the verses are expounded in detail. In addition, the detailed derivations and proofs of the statements and algorithms are presented in the upapattis. Study of the vasana is indispensable for understanding the methodology of, in particular, and thereby, of Indian astronomers in general. The distinct scientific method of Bhaskara (indeed of the Indian astronomical tradition in general, of which he was a leading exponent), his approach to problems and the ways to solve them, can be understood only when one goes through the commentary and understands it. It is for this reason that the Vasanabha?ya has been translated into English for all the verses, for the first time. Explanatory notes based on the vasana of Bhaskara have been provided for all the verses in modern notation, with a large number of diagrams to facilitate the understanding. The first volume of the book comprises the three chapters on Madhayama (Mean longitudes), Spa??a (True longitudes) and Triprasna (the three problems) with about 300 verses. Scholars working in the area of history of Indian astronomy and mathematics will find the present work on this major text of Bhaskaracarya with his auto-commentary, very valuable . In fact, anyone with an undergraduate-level knowledge of mathematics and serious interest in Indian astronomy will find this work very useful for understanding the subject, as it is reasonably self-contained.
