This brief but thorough treatment of the history of the doctrines of Christianity starts out by showing what the structure of belief was that started with Jesus teachings and how that affected the teachings and spread of the Gospel from Jesus through the Apostles to the early catholic church. The next topic dealt with is the rise of one of the greatest heresies in the church, Gnosticism. Harnack is able to observe and lay out how the spread of the doctrines of the early church were able to create a breeding ground for the gnostic heresies and goes over the details of some of those heresies. This treatment of the early church is a valuable tool to any true scholar!