I recently completed Gary Dexter's book Title Deeds which goes through some 50 literary titles (from Dante's Divine Comedy to Coupland's Generation X via Erewhon and The Great American novel) and discusses the works. It is a companion volume to Why not Catch-21 which looks at another 50 (Plato's Republic to Mamet's Oleanna via Moby Dick and 1984, etc). Both books provide an overview of lterature as well as some interesting sidelights on title choosing. Dexter has a mothballed blog here that discusses 181 titles altogether.
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.