I have had the book Letters to Malcolm: Chiefly on Prayer by C.S. Lewis on my book list for some time now and finally got around to reading it. The book was published in 1964, a year after Lewis' death. According to what I found online, it seems that this book is generally considered to be a lower tier work compared to others that he wrote on Christianity. One wonders if Lewis had ever planned to release it for publication or if it was still in a draft form.
However, my opinion is that this book is very typically Lewis. It contains his unmistakeable imprint. His style. His deeply probing questions. His thoughtful and logical considerations. I suspect that the real issue is the style and format of the book. This work is laid out as a series of letters between Lewis and an imaginary friend and colleague, Malcolm. The approach is that we are seeing one half of an ongoing dialog between the two men where they regularly write back and forth on the topic of Christian prayer and other areas of concern for those who are dealing with issues of faith. The difference is that in this, albeit more casual style of a personal letter, Lewis often asks questions that he doesn't fully lay out answers to. It is also the case that he leaves open many things for interpretation and exposes himself to questions regarding certain approaches to prayer and church that were being debated at the time.
Yet I do not think this approach a weakness. In fact, it makes you think and consider. It gives you room to voice your own opinions and form your own arguments. This framework allows you to be part of the dialog and discussion. I very much enjoyed my time with this short work.