When the First World War froze into a static line of trenches stretching from the North Sea to the Swiss border, the most obvious means of protection against the murderous machine-gun fire which both sides inflicted upon each other was some form of shell-proof shelter which from which fire could be returned in safety, hence the development of the pill box. The idea was certainly not new but the technology required to build them under the prevailing circumstances presented problems hitherto undreamed of. In this remarkably absorbing study of what at first seems a somewhat arcane study of what at first seems a somewhat arcane subject, Peter Oldham, himself a concrete technologist, examines the problems of the design and construction of the pill boxes of the Western Front. He describes how the innumerable difficulties involved in what might to the untrained eye seem to be a fairly simple structure, were gradually overcome. Containing as it does, a gazetteer of the remaining pill boxes and bunkers still to be found in Flanders and Picardy, this book will prove an invaluable guide to the members of many clubs and societies which annually make pilgrimages to the battlefields of the First World War and certainly add a new dimension and interest to their visits to the Western Front.