Having read and enjoyed Penelope Fitzgerald's The bookshop I remembered that I once owned her Blue Flower although I'd not read it. So on to the Internet and a new copy - foolishly I wanted the cover as above. Anyway it added to the pleasure. The Blue Flower tells a story from the early life of the German poet Novalis. I could tell you the plot, insubstantial as it is, but that was not where the pleasure lay. This is one of those novels where the fun is in the brilliant way that she inhabits her characters and brings them alive in a way that draws you in and makes you so familiar with them they are real (as in this case they were, but you know what I mean). It is quite a skill and when you out a book like that down it is like the end of a great symphony. You feel some sort of echo lingering after it, There aren't many books in that league. Anyway I'm now reading a non-fiction piece she wrote on her father Edward Knox and his three brothers. I actually became aware of this when I saw it footnoted in Iain Murray's biography of Ryle.
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.