The historical section is a fairly brief overview right at the start, you can finish that pretty quickly if that's what you are interested in. Personally, I found it curious and useful. Doctrine of Awakening is also a very good book in general if you want to get an insight into the methods and aims of religious traditions. It can be a dense read at times, especially if you have little interest in or intention to practice Buddhism, but reading it was a turning point for my understanding of spiritual traditions and decisively persuaded me to abandon materialism.