St. Isaac of Nineveh, or, as he is sometimes known, St. Isaac the Syrian, was born in the region of modern Qatar and lived during the seventh century. Ordained as the bishop of Nineveh sometime between 661 and 681 CE, Isaac withdrew from his ecclesiastical office after only five months, retiring to live as a monastic hermit in the mountains of southeastern Iraq. Translated from their original Syriac into a number of other languages, St. Isaac's spiritual writings have been read by Christian monastics for centuries. The present volume gives the original Syriac text edited by Paul Bedjan.