The Kephalaia gnostika comprises 540 chapters (90 chapters in six "centuries") discussing the highest levels of spiritual and natural observation. The work, which is the final part of a trilogy that begins with the Praktikos and the Gnostikos, is marked by philosophical erudition and is written cryptically. It is generally considered to be a core text behind the condemnations of Origen in 553. Because of how little survives in Greek, the Syriac translations are key, especially the so-called unexpurgated version (termed version S2).