John Frame has been on the forefront of a rising tide of apologists and theologians who are turning to an apologetic method commonly called Presuppositional Apologetics. Though there are some who would amend the name to Covenantal Apologetics (K. Scott Oliphant) or Expository Apologetics (Baucham Jr.), the basic biblical tenants remain the same. I think the basis for this type of method shines most brightly in the newly revised edition of Apologetics: A Justification of True Belief.
Frame starts with the banner verse of apologists everywhere, 1 Peter 3:15. Where others would point out that apologetics comes from the Greek word apologia mentioned there in verse 15, many fail to mention that the verse also calls us “sanctify Christ as Lord in our hearts”. It is on that premise which Frame builds his case and his foundation for the endeavor to engage the unbeliever and the skeptic.
As a contrast to the classical method, the presuppositionalist begins with the propositions set out in Romans 1, namely that mankind is in open rebellion to God and seeks to reason autonomously thus placing himself, not God, in the place of ultimate authority. The classical apologist seeks to find areas of common ground with the unbeliever and work towards convincing the skeptic towards God. They maintain that the Bible is not the best place to start, an error according to Frame.
What Frame does in this volume is not to give an analysis of the method he has spent a life perfecting, he wants to build a framework (no pun intended) which the reader can use to judge arguments by. On a side note Francis Schaeffer sought to do the same thing as Frame, though he was thinking along the lines of Worldview ideas and not apologetics directly.
I would wholeheartedly recommend this as a perfect place to start in the area of apologetics. It certainly should not be the only apologetics text you own but it can help to reorient your thinking towards the bible as you encounter various thoughts on truth. Along with guys like Geisler, Oliphant, Os Guiness, and Zacharias, this volume is first among equals. Get it. Soak in it. Let it transform your entire way of thinking. You will not regret doing so.