Without a doubt, the most enjoyable book I have read this year is Delighting in the Trinity by Michael Reeves. I think I enjoyed it so much because it dovetails with something the Lord has been teaching me over the past few years, namely, that the triunity of God is urgently relevant to everything about Christianity and the Christian life. Preaching through the Gospel of John brought it alive to me, and reading Augustine's works let me see in the life of one man.
Now comes the most recent issue of Credo Magazine, dedicated to the topic "The Trinity and the Christian Life." I encourage you to read it.