1) The earliest church fathers were primarily, if not totally, futurists, with regard to the way that they interpreted Revelation. This means that they believed in a literal Great Tribulation and Anti-Christ, the details of which are given in Revelation.
2) That these same men believed in a post-Tribulation Rapture of the Church. He is disputing the pretribulation premillenialism which is very common today via Tim LaHaye's writing. He also disputes the view of Revelation which is characteristic of Reformation Theology, which states that there will be no 1000 year earthly reign of Christ upon his return at all.
This is a good scholarly yet readable, and well-documented book. Here's an excerpt from the first chapter which give the nature of the rest of the book:
The question of the relationship of the Rapture to the Tribulation may be set in proper perspective if we first survey the history of prophetic interpretation. The hope the Church throughout the early centuries was the second coming of Christ, not a pretribulation rapture. If the Blessed Hope is in fact a pretribulation rapture, then the Church has never known that hope through most of its history, for the idea of a pretribulation rapture did not appear in prophetic interpretation until the nineteenth century.(19)