It would be difficult to point to anything which illustrates more clearly the arbitrary way in which the books of the Apocrypha have been separated off from the rest of the Jewish uncanonical religious literature of the period with which we are dealing than the study of the doctrinal teaching of this literature. For in the Apocrypha only part of that teaching is represented; to obtain it in its fulness, so far as the literature of the period is extant, we have to consult such pseudepigraphic works as the Book of Enoch, the Sibylline Oracles, the Testaments of the Twelve Patriarchs, the Book of Jubilees, the Psalms of Solomon, the Assumption of Moses, the Syriac Apocalypse of Baruch, and the Ascension of Isaiah. But to take all these into consideration here is out of the question, and we have already given a brief outline of the more important doctrines taught in them (Chapter X). There is, however, one compensation in restricting ourselves to the books of the Apocrypha; for the more important of these were recognized by official Judaism as containing good orthodox teaching; so that in dealing with this body of literature alone we are at all events on more or less secure ground as far as orthodox Judaism is concerned, and to get at that as a foundation is useful for the further observance of the development of doctrine. At the same time, it is necessary to bear in mind that while in most respects the books of the Apocrypha afford, speaking generally, a criterion for the period B.C. 200-A.D. 100 as to orthodox Jewish teaching, in some respects they are inadequate, in others even insufficient, so that in such cases recourse must be had to the Apocalyptic Literature, though we cannot here take that Literature into fuller consideration.