"A Dissertation on the Books of Origen against Celsus" by Francis Cunningham
Celcus was a 2nd-century Greek philosopher and opponent of early Christianity while Origen of Alexandria, also known as Origen Adamantius, was an early Christian scholar, ascetic, and theologian who was born and spent the first half of his career in Alexandria. In this book, Cunningham looks at how these two prominent men looked at the world and crafted two very different belief systems.