ISAAC THE SYRIAN (d. 700 CE?), also known as Isaac of Nineveh, was a bishop in the ancient Nestorian church of Syria; a monk, recluse mystic, and creative writer whose discourses have had widespread influence on Christian and, some think, Ṣūfī spirituality. The English world at first greeted his work, originally written in Syriac, with culture-bound coolness, but has eventually come to recognize him as one of the most sublime and original mystic writers of the Christian East.

Little is known about Isaac's life. Born in a region around the Persian Gulf, he became a monk and for a time the bishop of Nineveh (modern Mosul), an office he resigned after only five months. He then withdrew to one of the monasteries in the mountains of Huzistan (southwestern Iran), where he practiced strict solitude (hesychasm) as a way of pursuing unceasing communion with God. In...