Blue/green prismatic glass bottles are common at Roman urban and military sites in Britain. Many studies have indicated that they are more common at military sites than ‘civilian’ ones. The lower body is blown in a ceramic or stone mould, frequently including a stamp on the bottom. The upper body is then worked to form a flattened rim, and one or more handles are added to the neck and shoulder. Fragments of these bottles are highly diagnostic, as even a small body fragment can be identified due to the inside being glossy and the outside rough; however, this can sometimes lead to confusion between pieces from the wall of a prismatic bottle and window glass of the first to third centuries c.e., which is stretched on a ceramic former (leading to similar surface textures). Sometimes it is even possible to identify objects from the same mould or (arguably) from the same producer or groups using the same or similar symbols on the vessel’s base. Given all this, Cool’s new work is the first comprehensive study of this artefact type, building on some influential articles (including Cool’s recent offering in Britannia 53, 373–83). Cool has produced several influential, methodologically pragmatic, and practical publications on Roman glass in Britain, many with the late Mike Baxter (to whom this book is dedicated). This work is no different, and this book will be a key reference to anyone working on Roman (glass) artefact assemblages from Britain and the wider Roman world.

The book is divided into three sections: the first lays the necessary groundwork for the principal analysis with an introduction into the artefact type (1–18) and the nature of the data (19–29); the second lays out a series of seven families into which the square bottle corpus is divided (chs 3–7, pages 30–131) with chs 8 and 9 on hexagonal and rectangular/octagonal bottles respectively; the third includes a discussion of the chronological (ch. 10) and social and geographical (ch. 11) patterning of the data, as well as a detailed consideration of the uses of these bottles (ch. 12) and a conclusion (ch. 13).

Four appendices strengthen the utility of the work overall. Cool helpfully catalogues the 21 known extant moulds for these bottles (197–205) in Appendix 1 but, unfortunately, does not provide illustrations. The reader must then track down these references themselves, which may be easier for the seasoned Roman glass specialist (who likely has access to this literature) but will present an obstacle to a junior specialist or artefact generalist. One of the most comprehensive Cool cites (particularly for images), for example, is volume two of the Corpus des signatures et marques sur verres antiques (CSMVA), which is not widely available at British university libraries.

A particular strength of the volume lies in its illustrations. These are clear and consistent, and Appendix 2’s step-by-step superimposition to demonstrate mould parallels exemplifies the book’s didactic mission. Appendix 3 is a single table of data detailing the capacity of bath flasks analysed; this data underpins Cool’s attempt to compare the capacities of bath flasks and bottles in Ch. 12, which concludes with a persuasive argument that on the whole prismatic bottles were most often used for the household consumption of olive oil (193). Appendix 4 is a helpful orientation to the accompanying data stored with the Archaeology Data Service (ADS). These data include the entire catalogue of the material that underpins the book, bibliography, and illustrations, which increases the value of this contribution to scholarship.

Cool’s instructive and helpful narrative is present throughout, and her desired mission to educate and inspire the next generation of Roman glass specialists (explained in the preface) is admirable and detectable in the book’s tone. Cool’s volume is not a stand-alone guide to these bottles. Still, it is a perfect orientation in their study, and every glass specialist in an archaeological unit in Britain, and many overseas, will make great use of this volume. This is now the key reference work on the nature of these bottles and will underpin any future study of Roman glass assemblages (in which these bottles are nearly ever-present). Therefore, this concise, well-presented and well-illustrated volume does precisely what Cool aimed to do. Cool sees great potential, when summing up, for analysing these square bottles as part of a ‘wider contemporary material culture found on different types of sites’. I hope readers share Cool’s (and this reviewer’s) opinion that glass has much to tell us beyond the traditional archaeological specialist report.