This book, overflowing with detail, examines the origins, content and divulgation of the related and, to some extent, competitive, pair of festivals celebrated on the 25 December and 6 January respectively. The competition arises from the overlap of themes and the provenance of the feasts. Both initially celebrated Christ's nativity; Christmas is western in origin, Epiphany (as its name shows) eastern. The adoption of the feasts belongs to the fourth century. So far the matter is agreed; from here we verge upon the moot. Little escapes Förster's keen eye; it is as well, because prejudice and ungrounded speculation have been rife. On the one hand, it has been claimed that the feasts were introduced as imitations or substitutes for pre-existing non-Christian festivals (a ‘history of religions’ approach which after a fashion echoes the English Puritan hostility to Christmas); on the other (by way of reply) that their date was based upon computation of the day of creation of the sun and the ideal human span of life for the new ‘Sun of Righteousness’ (Malachi iv. 2). Förster refutes both claims: the second conclusively for it makes no mathematical sense.The first is more plausible but founders on the non-existence of any comparable winter solstice festival for which Christmas could substitute and on the hostility of church authority to non-Christian festivals: a fast, he remarks, was the natural response not a feast. The suggestion that the Basilideans might have inspired the celebration of 6 January is shown to be baseless. It may prove difficult, though, to shake the prejudice which the introduction of the modern Feast of St Joseph on the first of May evokes where competition with communism was certainly its reason. Moving to the details, Förster looks at the evidence from the Churches of the east, Rome and the western provinces for the introduction and content of the feasts. The disagreement between Jerome and Jerusalem, Epiphanius' rationale for the dates in Christ's ministry, the arguments (shown to have been consciously false) of John Chrysostom at Antioch in favour of the introduction there of Christmas and Gregory Nazianzen's triad of Christmas and Epiphany Orations 38ff. (such as they are here claimed to be) are all discussed, Gregory being the first witness to Epiphany as commemoration of Christ's baptism. Förster speculates that pressure from Theodosius, recently arrived in Constantinople and keen to keep in step with Rome, lay behind the novelty of a celebration in the capital of Christ's birth on 25 December. I think there may just be something in this speculation. Popularisation of the feasts is plausibly ascribed to the growth of pilgrimage especially to Jerusalem. No explanation for the choice of dates is forthcoming beyond evident ancient belief in their historicity. Overlong and repetitive the book may be but it treats adequately everything of importance, establishing the negatives (not substitutes for pagan festivals, not dated from arcane calculations) and leaving at least one unanswerable question (why 25 December and 6 January?).