Avicennas Addendum to His Recension of Ptolemys Almagest

The Islamic astronomical tradition greatly benefited from the many works produced in different ancient cultures, as well as the new empirical and theoretical approaches that led to advancements in various aspects of astronomy. Nevertheless, a significant portion of the history of this tradition, especially its formative period, was lost or remains undiscovered. Avicennas addendum to his recension of Ptolemys Almagest, which he incorporated into his main philosophical summa, Kitb al-Shif, helps recover parts of this otherwise lost history. In the addendum, Avicenna took a historiographical approach and reported the developments in the science of astronomy that occurred from Ptolemys time until his own. As such, the treatise also sheds light on the sources that were possibly available to Avicenna. However, because Avicenna did not explicitly indicate his sources, and because the texts structure is complex and language condensed, analyzing the treatise is a rather challenging task. The present monograph offers a critical edition of Avicennas addendum, complete with an English translation and commentary, to assist readers in better understanding and appreciating this valuable contribution to the history of Islamic astronomy.