The word “apocalyptic” is popularly associated with fanatical millenarian expectation, and indeed the canonical apocalypses of Daniel and especially John have very often been used by millenarian groups. Theologians of a more rational bent are often reluctant to admit that such material played a formative role in early Christianity. There is consequently a prejudice against the apocalyptic literature which is deeply ingrained in biblical scholarship … Whatever we may decide about the theological value of these writings, it is obvious that a strong theological prejudice can impede the task of historical reconstruction and make it difficult to pay enough attention to the literature to enable us even to understand it at all. - John J. Collins