This book offers a groundbreaking exploration of Galileo Galilei's engagement with the Almagest, Claudius Ptolemy's second-century scientific work on the motions of stars and planetary paths. Contrary to the belief that Galileo had little interest in Ptolemaic astronomy, the author investigates whether Ptolemy influenced Galileo's shift to Copernicanism, the theory that Earth and all other planets revolve around the Sun. This inquiry is pursued through a detailed examination of Galileo's ea ...