DOBRZYCKI'S LEGACY Selected Papers on Medieval and Renais sance Astronomy. Jerzy Dobrzycki, edited by Jaroslav Wlodarczyk and Richard L. Kremer (Studia Copernicana, xliii; Warsaw, 2010). euro29. ISBN 978-83-86062-03-4.Jerzy Dobrzycki (1927-2004) was the pre-eminent Polish authority on Nicholas Copernicus during the second half of the twentieth century. He contributed to the study of early modern astronomy across a wide spectrum and edited Polish, Latin and English editions of De revolutionibus. Many of his shorter pieces have now been brought together in one volume of the ongoing series Studia Copernicana, sponsored by the Institute for the History of Science of the Polish Academy of Sciences in Warsaw, which he formerly directed.The collection begins with Dobrzycki's notable study 'The theory of precession in the Middle Ages, newly translated by A. Niemirycz, and here available for the first time in English. In addition to medieval theories, especially the theory of trepidation descending from Thabit ibn Qurra, Dobrzycki presents the historical background of precession theory in Ptolemy. He concludes with a detailed consideration of Copernicus and brief remarks on Reinhold, Clavius, Schoener, Kepler and Tycho. Two brief papers on calendar reform follow.Another substantial paper is a collaboration with Richard L. Kremer, and Maragha astronomy? The ephemerides of Johannes Angelus and their implications (this journal, xxvii (1996), 73-123). Angelus (d. 1512) published two ephemerides which he claimed were based on an unfinished work of Georg Peurbach. Dobrzycki and Kremer confirmed Angelus 's claim that his results differed significantly from planetary longitudes based on the Alphonsine tables. They argued persuasively that these differences resulted from the addition to the standard Ptolemaic models of a mechanism generating harmonic motions. The best known of these devices (today) are the Tusi couple and Ibn al-Shatir's double-epicycle arrangements. After arguing on internal grounds that the novelties in these tables do, as Angelus says, originate with Peurbach, they eliminate a variety of other possible ways of physically instantiating the devices that would add the necessary harmonic features, and conclude, We are left, then, with the distinct possibility that Peurbach employed some version of the Maragha techniques in his modified models. This, it turns out, is not the only evidence that Peurbach may have had access to some version of Tusi's work. As Dobrzycki and Kremer point out, Peurbach refers to a latitude model of Ibn alHaytham that is now lost in Arabic, was apparently never translated into Latin, but is described by Tusi, in his Tadhkira. As they also note, J. L. Mancha has suggested that astronomers from Henry of Hesse to Albert of Brudzewo may all have used some version of this theory of al-Haytham, suggesting access by way of Tusi, or a later commentary on Tusi, or some later Islamic astronomical text. …