In the late fourth century, the early Christian monk and author Evagrius Ponticus wrote his magnum opus in Greek--entitled Kephalaia Gnostika ("Gnostic Chapters")--a spiritual treatise on ascetic contemplation and unity with God. After Evagrius' death, however, his theology attracted controversy, and many of his writings were suppressed or destroyed. As a result, complete copies of this important work principally survived only in Syriac translations and an Armenian adaptation, until the recent discovery of two Arabic copies at the so-called Monastery of the Syrians in Egypt. The present volume represents the first-ever critical edition and translation of the Kephalaia Gnostika in that language.