This book is a Bible study on biblical election (God's choosing of His believers). It is a study dealing with people's choices in light of God's choices and sovereignty.
Many questions arise from this subject: Do I exercise my will, or is everything predetermined? Do I have a "free" will? How does God's sovereignty really work? Am I just a puppet with God pulling the strings? Can I truly love God if my will isn't really "free"? How does God's "foreknowledge" apply to my salvation? How much involvement do I really have in my own salvation? These are difficult questions to be sure.
We can observe the Bible dealing with this subject from two very different perspectives:
The horizontal perspective: Mankind's perspectives and actions. The exercising of people's will and choices as they participate in life and relationships around them.
The vertical perspective: God's perspective and actions, outside of people's perceptions. It requires God revealing these things in His Word for us to know about them.
The book deals with the obvious occurrence of people exercising their wills (which is observable - the horizontal perspective). It also looks at what the Bible reveals to us about what God may be doing behind the scenes (which cannot be observed - the vertical perspective).
Even though a few illustrations and analogies are included, this book relies heavily on the topic as dealt with from the pages of the Word of God.