To understand this book, or any book, I recommend first learning a little about the author.
And so, I have included the wikipedia article for your edification. Though brief, and insufficient in capturing the grandeur of Mr. Lewis, I found that this article was apt enough for my own purposes.
I hope, if you hopefully intend to read along, that you will enjoy and participate in discussion of key themes and topics. This vain desire, however doesn't necessarily mean that you won't necessarily enjoy reading my summaries and reflections, due to Lewis' habit of capturing life's issues and truths often in his works.
Having said as much, I hope you will enjoy and participate. Best of luck in all you do.