In 1960, after a climbing accident in North Wales, Al Alvarez’s broken leg was set so badly that over the next thirty years all the cartilage in his ankle gradually wore away. By 1993, aged 63, this hard man of letters could barely hobble to the foot of a rock face, so he reluctantly gave up trying and turned instead to cold-water swimming to deliver the adrenalin rush that he used to get from dangling off mountains. Thus began his daily pilgrimage to the ponds on Hampstead Heath, where he first swam when he was 11. His ten-year journal of these morning dips makes up this haunting book, which began as a swimming diary but turned into a chronicle of getting old.

The summer entries are less compelling than those in winter because, as Alvarez himself says, ‘swimming only becomes a subject to write about when the temperature drops and it becomes a challenge … a dare, a morsel to feed the rat’. On a typical