In this and its companion volume, Dr. Barclay makes the most difficult book in the Bible easier to understand. In his introduction he examines areas such as the characterstics of apocalyptic literature and the nature of Caesar worship, John was, as Dr. Barclay shows, "soaked and saturated" in the Old Testament, and most of the imagery he employs is drawn from that source. Dr. Barclay does more than clarify the meaning of the imagery. His commentary covers many interesting subjects, such as the seven gifts of the Holy Spirit, the probable facts about John exile on the island, and the meaning of Christ's knocking at the door.