The problem of the date of Isaiah xl.-lxvi. is this: In a book called by the name of the prophet Isaiah, who flourished between 740 and 700 B.C., the last twenty-seven chapters deal with the captivity suffered by the Jews in Babylonia from 598 to 538, and more particularly with the advent, about 550, of Cyrus, whom they name. Are we to take for granted that Isaiah himself prophetically wrote these chapters, or must we assign them to a nameless author or authors of the period of which they treat? Till the end of last century it was the almost universally accepted tradition, and even still is an opinion retained by many, that Isaiah was carried forward by the Spirit, out of his own age to the standpoint of one hundred and fifty years later; that he was inspired to utter the warning and comfort required by a generation so very different from his own, and was even enabled to hail by name their redeemer, Cyrus. This theory, involving as it does a phenomenon without parallel in the history of Holy Scripture, is based on these two grounds: _first_, that the chapters in question form a considerable part--nearly nine-twentieths--of the "Book of Isaiah;" and _second_, that portions of them are quoted in the New Testament by the prophet's name. The theory is also supported by arguments drawn from resemblances of style and vocabulary between these twenty-seven chapters and the undisputed oracles of Isaiah; but, as the opponents of the Isaian authorship also appeal to vocabulary and style, it will be better to leave this kind of evidence aside for the present, and to discuss the problem upon other and less ambiguous grounds.