This book by C. S. Lewis was adapted from a 1943 series of radio broadcasts. It is a wonderful work in Christian apologetics.
To form the information obtained in this book Lewis interviewed Christian believers of all kinds; Catholic, Presbyterian, Anglican, etc. His purpose was to find those points that nearly all Christian religions agree upon. He sought to avoid controversies in order to explain those things that are common to all Christians in all places and times.
Lewis takes an amazingly academic and intellectual approach to Christianity. In fact, the first half of the book does not talk about Christianity. He starts with the question of, is there right and wrong? From there the book leads the reader on a rational and systematic path that is full of intellect, reason and common sense. Each point builds on the undeniable conclusion of the previous point.
By the middle of the book the reader is convinced of a one true God and His son. Lewis continues his logical approach to culminate with the sound conclusion that Heaven exists, and the only way to it is through Christ.
This is one of the most amazing apologetic works written. It is perfect for intellectual, nonbelievers that suppose Christianity is the product of dimwitted simpletons. In this book Lewis does not use the Bible or doctrine to prove the existence and God and Christ. Lewis uses logic, philosophy, science and modern reasoning to prove that their can be no commonsense alternative to the existence of one true God.