The word theology sounds intimidating, but it really just means the study of God. Though we will never fully understand God, at least not on Earth, we aren't excused from learning what we can. The Bible is the word of God, which is where we should start and The Moody Handbook of Theology, by Paul P. Enns, is kind of like a study guide, albeit, a large one.
I have seen other theology books that are very in-depth and hard to read. This one, even with its length, is not bad to read. It isn't something I'm going to sit and read cover to cover in a short period of time, but it is pretty easy to read. It covers a lot of topics that, whether we fully understand them or not, we should be aware of. It compares Calvinism to Arminianism, shows how theology varied in different historical time periods, and covers theology of New Testament writers such as Paul and Peter.
I wouldn't say that this book will have you understanding everything. It does provide a wealth of information in a way that is straight-forward and helpful. It is a good companion book to use in personal Bible study to to prepare lessons.
I received a free copy of The Moody Handbook of Theology from Moody Publishers in exchange for an honest review.