I found this book fascinating. Lewis delves into hell for his characters Screwtape, one of the Devil's assistants, whose job is to stop people becoming Christians. The novel (for I would classify it as such) is presented as a succession of letters from Screwtape to his nephew, a younger, newer 'demon'.
This is a really entertaining read, and immensely funny. It challenges preconceptions of how we view Christians and it makes us think about how our daily actions have much larger repercussions. Lewis presents each of our lives as a battleground between good and evil.
Despite the depth of this book, it is a lighter read than you would imagine. Lewis offers us a lot of hope and encouragement in a world that seems to be influenced by the Devil at every turn. Lewis highlights the futility of evil where a benevolent God is truly in control. A must-read no matter what your beliefs.