Revelation 8:1-2 "When He opened the seventh seal, there was silence in heaven for about half an hour. (2) And I saw the seven angels who stand before God, and to them were given seven trumpets."
It is when our Lord Jesus opens the seventh seal of the scroll, that the wrath of God will begin to be poured out on the earth. Just prior to this event, the rapture of the church will have taken place. When the event of the rapture takes place, the inhabitants of the earth will be continuing with their daily lives completely unaware of the devastation that it about to come upon them. This book describes what will take place in the earth during this time.