C  2007 Institute for Research in Classical Philosophy and Science All rights reserved ISSN 1549–4497 (online) ISSN 1549–4470 (print) ISSN 1549–4489 (CD-ROM) Aestimatio 4 (2007) 201--206 The Birthday Book: Censorinus translated by Holt N. Parker Chicago/London: University of Chicago Press, 2007. Pp. xiv + 102. ISBN 978--0--226--09974--3.Cloth $25.00 Reviewed by Robert Hannah University of Otago, New Zealand robert.hannah@otago.ac.nz The little Birthday Book (De die natali liber ) by the third century AD grammarian, Censorinus, was originally presented as a birthday gift to his friend Quintus Caerellius in AD 238—the date is derived from the text itself, where it is expressed allusively and eruditely as the year 986 of the era of Nabonassar [De die nat. 21.9]. The Birthday Book uses the idea of the birthday as the starting point for a brief but virtuosic survey of the measurement of time itself. What the book says about time is not particularly original, but it is useful from a cultural perspective inasmuch as Censorinus demon- strates a breadth of learning that was typical of his class and time. From an antiquarian point of view, the essay is especially valuable for what it reports from earlier authors whose works have not survived, notably the early Imperial polymath Varro. In what has survived of the Birthday Book itself, the first half [cc.1--13] takes the idea of the birthday as the starting point in an analysis of the development of human life from conception to death. The second half [cc.16--24] then discusses the various measures of time from eternity down to the hour. It may be, as Parker suggests [56--57], that the work was meant to be balanced around the encomium to Caerellius in chapter 15, and to finish with a further five chapters to provide a coda that returned to the honorand’s own birthday, perhaps with his horoscope: this would also nicely draw together some of the preceding themes. The book is a compilation-piece, then, but one in which Cen- sorinus demonstrates his own remarkably wide knowledge and his easy ability in passing it on to his reader(s). One may reasonably judge that he knew a little about a lot and had skill in knitting it all together, however disparate the items may look at first glance. Un- derlying this knowedge lies the basic curriculum of ancient Classical