Limbaugh's earlier book, The True Jesus, examined the four Gospels. In this book, he focuses on the book of Acts, especially the missionary journeys of Paul, and then on the following letters from Paul: Galatians, Thessalonians 1 & 2, Corinthians 1 & 2, and Romans. For each of these Bible books, the author provides some historical and theological background, and then discusses major events or themes in that book.
I found this to be a good companion piece to reading these Bible books and to understanding how the early Church began to spread throughout the world. Sometimes its easy to forget that the authors of the Gospel and subsequent books of the New Testament didn't have a New Testament to work with! That is, they were Jewish converts who had only the Old Testament as their Bible.
In that sense, this book helped me understand Paul - his determined persecution of Christianity, which he saw as a threat to his Jewish faith; his conversion on the road to Damascus, and his passionate persistence in building the Church for the rest of his life. And especially how Paul evangelizes that Christ is the fulfillment of the Old Testament covenant between God and his people. Also very interesting to better understand Paul's work in keeping the early Gentile churches (e.g. Corinth) on the right track, as they deal with internal struggles and theological arguments.