Mike and I are reading Rick Renner's book, A Light in Darkness. It's one of three volumes and is the only one in print at the moment.
A huge book, it's full of wonderful historical facts concerning the early church, the disciples, the Roman Emperors, Patmos, etc. . It will primarily cover the seven churches in the Book of Revelation but he has done such extensive research giving us such a wealth of history during this time frame.
It's a wonderful history book! Also one you can't read too quickly, there's just too much delicious information to digest at one time.
So we are reading it like you would "eat an elephant"...one "bite" at a time!
We highly recommend it!