Second Epistle to the Thessalonians
This book is believed to a letter from the Apostle Paul to a church in Thessalonica a part of ancient Greece.  Thessalonica was the second city in Europe where Paul taught and left a Christian church. After the first letter was sent, probably soon, some of the Thessalonians were not sure that those who had died would share in the Second Coming of Jesus. This letter was written to answer this concern.