Working in the Public Record Office some years ago, I ordered up the logbook of the badly damaged HMS Scylla on her return to Britain after D-Day. There was something very moving in seeing the bare navigational details noted in my uncle’s familiar hand. But then can anything be so immediate a point of contact with the past as a ship’s log as, watch by watch, the location, the wind and the weather are recorded with relentless discipline? Is there a more eloquent message than the odd water stain during a ‘fresh gale’? And if this is telling, what of...