Still trying to read some shorter classics. I picked up Graham Greene's The Third Man from the Library the other day. It also has the short story Fallen idol (also known as The Basement room) with it (online see here). See here. Both were made into films in the forties or fifties. I seem to remember seeing some of The Third Man once on TV with its haunting zither theme (by Anton Karas). The book itself is fine for what it is, the story of a small time racketeer. I presume it was written for film. It's very cinematic. It seems to capture a now gone world and the story of a few caught up in it.
Bonhoeffer uses a similar phrase 'worldly Christianity'. It's J Gresham Machen that I want to line up most closely with. See his Christianity and culture here. Having done commentaries on Proverbs (Heavenly Wisdom) and Song of Songs (Heavenly Love), a matching title for Ecclesiastes would be Heavenly Worldliness. For my stance on worldliness, see 3 posts here.