This series is a note-formatted commentary set on the biblical book of Revelation. Revelation 10:11 states that “in the days of the seventh angel, when he shall begin to sound, the mystery of God will be finished. . . .” The book of Revelation is divided into seven sections, and a volume is devoted to each section. The format is not “verse-by-verse,” or “answer all,” but provides notes to aid students with suggestions for the more difficult passages, or to elucidate dark portions, or to observe things often overlooked in other works. This first book addresses the “churches” section of Revelation 1-3.