Howard Jones gives what seems to me a very fair summary -- despite having not yet read the book. But I would add one comment. The transmission from the printed form(s) (which were surely in most cases the forms which achieved wide distribution, whether or not one of them was the original) to the collected versions was in most cases via only a few steps of transmission, in the course of which the variation went in more than one direction, but often in the direction of degeneration rather than refinement.