I recommend that the The Milk Is White be read before The 'Quo Vadis?' File III because the book predates the "File". Hence, the "File" qualifies and/or expands upon the contents of the book.
In recommending that the reading of the book precede the reading of The 'Quo Vadis?' File III, I use the analogy that to pick out and eat bits of fruit from a fruit cake without eating the cake does not give one the experience of the texture, the taste and quality of the whole.
Be this as it may, it is not for me to interfere with the choices of anyone.
NB. In The Milk Is White note the quotations on the lead pages.