St. Bonaventura (1221-1274) found that there are basically four ways of 'making books' (modi faciendi librum):"A man might write the work of others, adding and changing nothing in which case he is simply called a 'scribe' (scriptor).""Another writes the work of others with additions which are not his own; and he is called a 'compiler (compilator).""Another writes both others’ work and his own, but with others’ work in principal place, adding his own for purposes of explanation; and he is called a 'commentator' (commentator) …""Another writes both his own work and others' but with his own work in principal place adding others' for purposes of confirmation; and such a man should be called an 'author' (auctor).’"