The influence of Arabic-Islamic science on European astronomy is still evident in the number of terms and star names which derive from the Arabic. These articles examine what the Arabs - and other peoples of the Islamic world - knew about the fixed stars and the constellations, and the astrological traditions they associated with them. Professor Kunitzsch shows how the early folk astronomy of the Arabs was radically altered, without being swept away, by the discovery of ancient Greek, also Indian and Persian, sources; by far the most important of these was the Almagest of Ptolemy. This knowledge was then transmitted to medieval Europe, to Byzantium and, especially, to Spain, as the articles go on to describe, and was a vital factor in stimulating the development of scientific thought in the West.