Mary Shelley (1797-1851) I thought it was about time we got back to the novelists series. Given the date John Polidori (author of The Vampyre) would have been good but the author of the gothic novel Frankenstein or The Modern Prometheus of 1818 is just as good. Mary Wollstonecraft Godwin was a novelist, short story writer, dramatist, essayist, biographer, and travel writer, but is best known for her much copied novel. She also edited the poems of her husband Percy Bysshe Shelley, whom she married after scandalously eloping with him to Italy and after the suicide of his first wife. Her husband drowned six years on. She wrote at least five other novels.
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.