Actually I would suggest a more complete collection of Ronald Knox's works, but if there was ever any particular one that I should like to see is his free translation of the Latin Vulgate.
His writings appear to have all the hallmarks of greatness like Chesterton (I'd like to see his "Saint Francis of Assisi book) and CS Lewis and would be just as viable as John Henry Newman's complete works.
He seems like an interesting literary critic also. How much of his influence helped shape Dorthy L. Sayers? I'd like to see her published essays to Charles William. (I'd like to see his works also). Of course, J.R.R. Tolkien, although he may not have much by way of theology, seems to have a huge influence with books written about the Lord of the Rings and Middle Earth.
Just some thoughts about a few other people whom I think have a great influence.