One person wrote:

To my disappointment, I discovered that Lewis doesn't really spend much time talking about atheism in this book. Despite his claim to have been one himself, his characterizations of atheism are to true atheism what a Tarzan movie is to Africa.

Unfortunately, to millions of Christians who read his works, Lewis's interpretation is the closest they will ever come to a discussion of this topic.

Another responded:

I wonder what the writer of the above paragraph means by "true atheism". That aside, Lewis discusses atheism in _Mere Christianity_ (45-46, MCII 1) and in 'Christian Reflections' (65-70) The discussion of Lewis of his atheism in _Suprised by Joy_ ( the book referred to above, I believe) is good as it shows CSL's mindset - anger, yes at a supposed Creator God who created the universe which Lewis thought was "a great injustice". He characterized these feelings as his bent toward "pessimism".

Just a note: Lewis did try his hand at apologetics, which were and continue to be successful. Lewis has been responsible for the conversion of untold numbers of people.