Silk Roads by Peter Frankopan is over 600 pages long and I am not very good at reading long books. One of my sons and his wife gave it to me as a present, however (last birthday maybe even Xmas 2016?) so I felt under some obligation, thankfully. The book is subtitled A new historoy of the world and so it has been worth wading through in order to fill up several gaps in my knowledge. It also takes a middle eastern and central asain viewpoint in the main and so is new in that sense also. It is good to eb reminded how much on the edge we are out here in Britain. Iwas slightly surprised to be reminded how involved Britain and then the USA has been in thhat part of the world. I have already forgotten much of the detail of fairly recent events in Afghanistan, Iran, etc. Do geta hold of it if you like big books or if you just like history.
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.