The long-awaited updates of the British Regional Geology guides continue to appear slowly but surely with the publication of the volume on Wales. In a sense, we get two volumes for the price of one here, because previous editions separated the principality into guides on North Wales and South Wales. The Geological Survey has wisely decided that this subdivision along a geologically arbitrary line serves no good purpose. The whole of Wales is therefore covered, but the Welsh Borderland to the east is still reserved for a separate volume. This scheme has the logic that the political boundary of Wales is at least partly influenced by geological factors.

The detailed synthesis of an area of the size and diversity of Wales would now normally be seen as a multi-author task. The new volume is therefore notable for having been written by one person, Malcolm Howells, and after his formal retirement from the Survey at that. There are few other people who could have completed this task so successfully. For sure, he will have had the advice of specialist colleagues, but Howells' writing style runs through the whole volume and gives it a pleasing coherence. Ample illustrations enliven the text. Line drawings, mostly in colour, are drafted to a high standard, and a good selection of colour photos gives an excellent taste of the field geology of Wales. A 1:625<2>000 geological map of Wales accompanies the book.

With the design and presentation of the guide brought up to date, it is nevertheless comforting to find the traditional chapter headings, mostly the geological periods or eons; Precambrian to Cainozoic. These core chapters are flanked by an introduction and a concluding chapter on Geology and Man. I might have added only a chapter on structure, including geophysics, as in the recent guide to the Pennines. The gravity and magnetic data on Wales add significantly to our understanding of its substructure. A structure chapter would also have avoided the anomaly of describing the Acadian deformation in the Silurian chapter, when it properly belongs in the Devonian.

The publicity for the regional guide states that it is ‘aimed at geology students and advanced amateurs as well as professionals who need an overview of the geology of Wales’. The guide is well crafted for this readership, bridging the gap between the popular styles of the new 1:50<2>000 sheet descriptions and the weighty information in the old memoirs. We look forward to future volumes in the series.