Ladd is probably best known for his work on the "kingdom of God," but he is also noted for his insight into Christian eschatology (which I've written about before). He is also hailed for reviving biblical scholarship in the years after the second world war.
This book is academic (which you might have guessed by its size), but it is surprisingly accessible. I credit Ladd's writing skill, clarity of thought, and the overall organization of the book. It's easy to pick up and dive into any section. It's also engaging on a devotional level. As all good theology does, it deepened my love for Christ.
Yet A Theology of the New Testament did more than hone my perspective on the kingdom or eschatology. It opened my eyes to the world of biblical theology of which I was hitherto unaware. I had previously only been exposed to systematic theology. To be clear, both "biblical" and "systematic" fields of theology put the Bible at the center of their study, but biblical theology focuses more on the historical development of the text and overall narrative of Scripture whereas systematic theology breaks down and organizes the text into comprehensive statements about specific topics. Much more could be said here, but that is the essential difference as I understand it.
Among other things, this book exposed me to a beautiful branch of theology with a refreshing level of wit and sagacity, helped me understand a fundamental aspect of Jesus' message (i.e. the kingdom of God), and demonstrated the significance of Christian eschatology. I'm deeply grateful for it. Maybe (hopefully!) someday I'll make it to Tom Schreiner's and G.K. Beale's versions.