The problem which Professor Décarie has chosen for investigation can be briefly sketched, since it is familiar. In indicating the superiority of the highest kind of contemplation to the departmental studies and to the arts, Aristotle terms it at one time ‘wisdom’, at another ‘first philosophy’, at another theology. The difference between the names seems not to be verbal, but to be accompanied by a real fluctuation of emphasis. So one question above all obtrudes itself upon the reader and is, indeed, propounded within the treatise itself in E I ( = K 7). Is the supreme theoretical science particular, being focussed upon the highest order of reality, upon pure form, upon the divine ? Or is it a comprehensive study of being qua being, which will not only consider the lesser categories of being (because these are held to be derivative from ousia), but contemplate more than one grade of ousia itself? On the one hand, the supreme science is occasionally called theologikê. On the other hand, it is also declared to ‘contemplate being qua being’, a phrase commonly understood to mean that it surveys from a certain aspect all that is real, leaving other aspects to other sciences.