You could try 'The Father Christmas Letters'.
Each year Tolkien composed a letter to his eldest son John, from 'Father Christmas', and the letters were eventually collected and published in this book.
John grew up to be a Catholic priest, and he was parish priest where I live, and married my wife and I.
Because i am not Catholic, I had to go for a couple of 'chats' in his study, basically to confirm that I woul agree for any children we had to be raised in the faith.
On the wall was a Tolkien calender, and a picture of the professor taken in his rooms at Oxford. Father T. pointed out that the settee in the background was the one i was sitting on, and the cadlesticks were on his own mantlepiece.
Looking at the mantlepiece, I saw two black and white photos of the professor. I know from his profile that the professor hated having his photo taken, and I asked Father T. how the two photoc came to be taken. he told me that the prof. was specifically asked by Lord Snowdon if he might take his pictire, and felt he couldn;t really refuse the brother-in-law of the Queen!