For anyone who does not read several dialects of ancient Syriac (Aramaic) fluently, this is a very valuable collection of translations of almost all the surviving documents written by Syrian Christians responding to the rise of Islam between about 630 and 750 AD. (Two documents for which full translations are being prepared separately are only summarized, but all the others are translated complete insofar as they refer to the Arabs, "Hagarenes" or in some cases "pagans" who took control of the region where these writers lived. As far as I can tell (not reading Syriac) these are generally fair-minded presentations of often fragmentary and sometimes obscure text. I will say that Penn's versions generally do not support the large claims by Patricia Crone in Hagarism that the Syriac sources give grounds for overthrowing the whole early traditional Muslim history of that faith, but I only noted one tendentious insertion (adding "worshippers of") to the word "Muhammad" in the important but barely decipherable 637 fragment). Penn seems perhaps more sympathetic to the scholars who argue Islam was originally a loose alliance of monotheists (including some Christians) but in general he seems to accept (as I do) that discrepancies between the Syriac evidence and Arabic Muslim evidence is usually due to simple misunderstandings and minor human errors. ( )