Here's a description that provides a brief overview:
In Part One, "the Objects of Knowledge," Frame focuses on what we know, particularly God, his law, the world, man as God's image, and the objects of knowledge in theology, philosophy, science, and apologetics.The reason I mention this is because there are a couple of helps online that you might want to be aware of: a study guide and an outline of the whole book.
Part Two, "the Justification of Knowledge," asks What right do we have to believe what we do? Frame addresses issues related to sensation and intuition, nature and Scripture, facts and criteria, and verification, presuppositions, circularity, certainty, and proof.
Part Three, "The Methods of Knowledge," examines how we obtain knowledge. There Frame discusses how we handle Scripture; how we may use the "tools" of language, logic, history, science, and philosophy to discover facts; and how a person's capacities, skills, and attitudes affect his knowing.
If you're willing to undertake an intellectual (and spiritual) workout, I'd encourage you to check them out.