C.S.Lewis wrote about self-deception throughout his career. It was his belief that the illusions we embraced did not only damage us spiritually, but impaired our ability to reason. Under the influence of personally convenient myths, we gradually can no longer even know simple things. Ideas which appear at first glance to be intellectual errors are revealed under examination to be something more emotional, more spiritual, more psychological. When I first began reading him I recognised not only the errors of others, but very quickly, favorite little theories of mine that were exploded in a minute under the force of his logic. His logic is a force, yes. Not always pleasant, but often profitable. In my twenties I considered it a challenge to my courage whether I would pick up another of his books.
Enjoyable, though. Fun, even, and quite quotable. You can use him to expose the ideas of others even if you have an ability to dart sideways yourself.
Not everyone here is a fan of Lewis, so I have no intention of cluttering up the front page here with a series of essays on him. However, I do link to the whole group for those who have interest.
8. That Hideous Strength. Not actually part of the series but added in for convenience
9. Self-Deception Anecdote. A later addition.