L Frank Baum (1856 – 1919) I don't think of as a novelist as this American author of children's books is best known for writing The Wonderful Wizard of Oz in 1900 which was later a very successful film (1939). Even though he wrote 13 novel sequels, nine other fantasy novels and a load of other works (55 novels in total, plus four "lost" novels, 83 short stories, over 200 poems, an unknown number of scripts, etc), and made numerous attempts to bring his works to the stage and screen he has only this one claim to fame. His works, they say, anticipated such century-later commonplaces as TV, augmented reality, laptop computers (The Master Key), wireless telephones (Tik-Tok of Oz), women in high risk, action-heavy occupations (Mary Louise in the Country) and the ubiquity of advertising on clothing (Aunt Jane's Nieces at Work).
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.