Count on the Saint is a mystery novel in The Saint series by author Leslie Charteris.
Charteris himself wrote which was done under his supervision.

This is a true hero, of the two adventures that comprise this book, the Shining Saint.
In a world of despair, sad literature and ugly characters, this is the best tonic.
Two more adventures for the Saint: in The Pastor’s Problem, Simon tries to help his penniless friend, Father Bernardo, by stealing a priceless silver goblet, only to discover some real crooks. In The Unsaintly Santa, even Cambridge University professors have to cry when a series of cold-blooded murders reveal a sinister plot on campus.