Our Sunday School Class has used this book for a base of study of the many effects that CS Lewis has had on the Christian. It is the most comprehensive biography of CS "Jack" Lewis written by someone who actually knew him and spent time with him for over 30 years. Not only does it give the reader an understanding of what and why Lewis wrote like he did. It also gives a perspective of life during the early 20th century in England. I also gained a better understanding of much classical literature because of the CS Lewis read volumns and Sayer talks about that too. A very worth while read.