Greek science was translated into Arabic in the 10th century, mostly by Nestorian Christians such as Hunain ibn Ishaq. The Moslem Caliphs of that period were the Abbassids, who came from Persia, and so knew the Nestorians as their “home” Christians. With their access to the Greek medical tradition, including the works of the 2nd century doctor Galen, they were consequently in demand as doctors. Of course being the personal physician of an oriental despot is not without risk, and Hunain himself was imprisoned, invited to act as a poisoner, and had his library confiscated.
But with all this, he managed to translate most of the vast output of Galen from Greek into Arabic. He also wrote a letter to one of his patrons, discussing this process. This is a very valuable guide to how Greek literature made it into Arabic.
A manuscript of the work was discovered at in the library of Greek texts at Agia Sophia and was printed by G. Bergstrasser, with a German translation, in 1925. Today I received a copy of the book by InterLibrary Loan, and I have scanned and uploaded the book to Archive.org, here. I have also added a Word document of the German text, also a .txt file and a .htm file.
An English translation and critical edition by John Lamoreaux is ready for publication. This is based on better manuscripts than Bergstrasser had. For this we shall have to wait. But if you can’t wait, and have some German, then you now can access Bergstrasser.
Bergstrasser himself vanished while climbing in the Alps in 1933, so his book is out of copyright in Germany, the EU and the UK. The US copyright status is unknown to me.