Most Lewis fans consider The Screwtape Letters his best work. Lewis himself felt it to be Till We Have Faces. The first excels at delineating spiritual warfare. The second delves deeply into the tortuous nature of the human soul. However, That Hideous Strength describes the battle between good and evil as it affects various characters in a world much like the one we live in. It builds off the conflict presented in the prior two works of the Space Trilogy, but it may easily be enjoyed alone. One of the great treats of the book is how Lewis depicts the wizard Merlin, and no other modern author does it better--not even T. H. White in The Once and Future King. That Hideous Strength counts as one of the 100 books one needs to read before one dies. Enjoy!