I was in The Works and I saw this little hardback covering Greek and Latin language, history, literature, philosophy. architecture and science and technology and fancied it for myself and hopefully for one of my sons who likes this sort of thing. I did a course on most of it in my first year in Uni and even toyed with the idea of learning Latin from scratch for half my degree. I suppose the Lack of Latin and the poor Greek is a bit of a regret but books like this do make so much accessible even for ignoramuses* like me. (* that is correct, I checked years ago).
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.