Evangelical Press's bitesize biographies have been coming out for a while now. I have read six of the ten that are out so far. I have enjoyed Chrysostom, Henry, Toplady, Macaulay, Schaeffer and Lloyd-Jones and am about to start on Renee of France (leaving Knox, Cranmer and Kivengere to come. Others are in the pipeline I believe). The discipline of keeping it to around 120 words (oops! Pages I mean, of course - Thanks Mostyn) is a good one and helpful to writer and reader. In the case of Lloyd-Jones and Schaeffer (Eryl Davies and Mostyn Roberts) the writers had the advantage of knowing their subjects. Both are excellent intros to important 20th century figures. Chrysostom (Earl Blackburn) delves the furthest back but is well done. I liked Philip Eveson's Matthew Henry for the way it told the story so well. Zachary Macaulay's important story was well told by Faith Cook too and left me wanting to know more (it led to me reading Arthur Bryant's Macaulay on the son, who sadly never came to faith). Singularly the EP book was marred by some minor errors such as typos. I was slightly disappointed with Douglas Bond's Toplady as it made too many references to extraneous matters for me. A good introduction nevertheless. This is a great series that will be of benefit to many people. Well done editor Michael Haykin and EP.
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.