Science made great, even revolutionary, strides in medieval Islam and Muslims and Arabic-writing non-Muslims (largely Christians, Jews, and Syriac-speaking Harranian star-worshippers who were thoroughly Hellenized by the time Islam emerged in history) share credit for the remarkable achievements in this field.
Indeed, Islam took over not only both the Alexandrian and Athenian Greek scientific legacies, which loom very large in complex ways in Arabic, dominant especially after the ninth-century, but it directly naturalized into its own cultural matrix a host of other scientific traditions too, in particular Persian, Harranian, Byzantine, and of course Indian traditions, cultivating at the same time Near Eastern Hellenism and Hermeticism, and espousing also some other attitudes and products of the Old World.
One is the fact that, as against the case with the Latin West, there existed a continuity here with the classical tradition: there were Hellenized academies and monastic schools in the Islamic territories that survived well into the early Caliphate period; then, at the same time, many communities steeped in the Greek intellectual tradition lived in these territories--the Harranians, Near Eastern Nestorian Christians, and Persians trained at the famous Sassanid academy of Jundishapur were particularly prominent among them.
The chart of Harranian festivals, showing a year tightly crammed with religious activities, is very interesting, but the chart cries out for interpretation.
On the whole, this book makes clear the dire need for a thorough interpretation of Harranian religion by someone with excellent credentials in astronomy, astrology, and the local history of religions.
It is unnecessary, too, to restate that the Mandaeans are not the same as the Harranian Sabeans, which is Gunduz' main argument.
These include the religious traditions of the pre-Islamic ("jahiliyyah") Arabs; Mazdeans in Mesopotamia, Iran and Transoxania; Christians (of different communions such as Nestorians in Mesopotamia and Iran; Monophysites in Syria, Egypt and Armenia; Orthodox Melkites in Syria, Orthodox Christianity in North Africa); Jews in various places; Samaritans in Palestine; Mandaeans in south Mesopotamia; Harranians
in north Mesopotamia; Manichaeans in Mesopotamia and Egypt; Buddhists and Hindus in Sind; tribal religions in Africa; pre-Islamic Turkic tribes; Buddhists in Sind and the Panjab; and Hindus in the Panjab.