Byzantine science has been a largely neglected subject: Byzantinists, whether dealing with the history or the literature, have most often been deterred by the technicalities; historians of Greek science have been more attracted to earlier periods. Yet, even if science in the Byzantine world may not have attained the levels of achievement of the Alexandrian period, or of the Islamic world, it is clear that it was the focus of serious scholarship, and this deserves equally serious investigation. Anne Tihon has been in the forefront of those bringing to light the wealth of unpublished texts. Her final study here presents an overview of scientific teaching in Byzantium, while other articles deal specifically with astronomy from the 9th to the 15th century. They look in particular at the relations between Byzantine and Islamic astronomy, and at calculations of the planets and eclipses.