The text originates from his radio messages during England's war with Germany; he added some material for the publication. Prior to its publication, he sent it to individuals from the Anglican, Methodist, Presbyterian, and Roman Catholic churches, to ensure that there was no particular "dogma" within its contents, he being a layman of the Church of England. And he listed the above denominations in alphabetical order so as not to make it appear he favored any denomination.
I am quite enjoying the read, and I have been a Christian for about 30 years.
For people who are even further gone than "unchurched", a C.S. Lewis anthology is a good gift - you're slipping them "Mere Christianity" in a stealth package. My brother is slowly but surely coming around - when I found out that he told my husband they were praying for me during surgery, I almost had a heart attack & had to stay on.
I'll second that recommendation. IMO, there is no better apologetic written in clear terms for the Gospel of Christ.
Worth reading more than once.
I see I didn't need to ping you either. Oh well. Have you read C.S. Lewis' "The Great Divorce" or "The Screwtape Letters"? Both are excellent.