Lieutenant-Colonel Claude Cunningham Bruce Marshall, known as Bruce Marshall was a prolific Scottish writer who wrote fiction and non-fiction books on a wide range of topics and genres. His first book, A Thief in the Night came out in 1918, possibly self-published. His last, An Account of Capers was published posthumously in 1988, a span of 70 years.
This enjoyably wacky satire is the third in a series of four books about the a Catholic Church gone off the rails. Set in the then future of the 1990s, the pope is married, has allied the Vatican with the Soviets, and has endorsed free love. His only real opposition is the Mother Superior of a traditionalist order of nuns who wishes to see the order's founder canonized, and who seems able to call forth divine intervention on her behalf, albeit in highly unusual ways.
The book is sadly out of print, but is available online at the internet archive. The dialogue is kind of repetitive. Indeed one of the sources of humor is the way certain phrases repeated over and over again, which manages to be simultaneously amusing and a little annoying. Overall, though, the book is well worth your time.