John Newman ends the introduction to his account of Monmouth in his fine new volume in the Buildings of Wales series by observing that the building of the by-pass in the 1960s, while essential to the survival of the town, unfortunately cut it off from the River Wye, its economic life-blood in previous centuries. But the Wye and its tributary the Monnow, which hold Monmouth in a tight grip, have done more than give the town its livelihood, as recent experience has once again reminded its citizens.