Isaac the Syrian lived the solitary life in the 7th century. He was born in Qatar and subsequently lived in present day Iraq and Iran. After life as a monk, then briefly as a bishop, he withdrew to live the solitary life. These discourses are primarily for solitaries to consolidate them in the love and mercy of God. In this volume, the text of Isaac V has also been included because of the light which it sheds on Apocatastasis, of increasing interest in academic and ecclesial circles.