Ehrman writes from a perspective of looking at the Jewish figure Jesus, so he says historically, rather than theologically. He often falls in the category of a critic, which makes him unpopular with some. How Jesus became God looks at the development of Jesus and the potential evolutions to his deity, that includes all Pagan theory's and possible influences.
There’s no other book like this that I’ve found. Often critics of Christianity’s version of monotheism place their view of one God in doubt, due to the belief of God as a trinity. However, you find a similar theme in ancient views of Judaism. That is before Judaism started defining itself as distinct from Christianity.
Within ancient Judaism, you find a belief of two powers or a plurality of two within their monotheistic one God. Today some have traded this view out for God appearing as multiple emanations, emanation as flowing out from a source or origin. The point here is when Jesus started being viewed as a divine person within the one God, it wasn’t the first time the masses heard something like this. It wasn’t a foreign view back then like it is today.
Ehrman is not a Christian. Nor does he desire to support mainstream Christianity. This leaves him with his detractors in that group. If you are alright with having what you believe challenged, it doesn’t mean you have to change your views. There’s a lot of historical information for armchair historians that you may enjoy.
There might be better books out there on this subject. I haven't even scratched the surface in my brief mention concerning the bulk of material that this book contains. For that reason, I'm going to hold off on recommending it. Your choice to read it.