In 1993, approaching my sixtieth birthday, I started to experience a curious phenomenon—the spontaneous, unsolicited rising of early memories into my mind, memories that had lain dormant for upward of fifty years. Not merely memories, but frames of mind, thoughts, atmospheres, and passions associated with them—memories, especially, of my boyhood in London before World War II. Moved by these, I wrote two short memoirs, one about the grand science museums in South Kensington, which were so much more important than school to me when I was growing up; the other about Humphry Davy, an early-nineteenth-century chemist who had been a hero of mine in those far-off days, and whose vividly described experiments excited me and inspired me to emulation. I think a more general autobiographical impulse was stimulated, rather than sated, by these brief writings, and late in 1997, I launched on a three-year project of writing a memoir of my boyhood, which I published in 2001 as Uncle Tungsten.1

I expected some deficiencies of memory—partly because the events I was writing about had occurred fifty or more years earlier, and most of those who might have shared their memories, or checked my facts, were now dead; and partly because, in writing about the first fifteen years of my life, I could not call on the letters and notebooks that I started to keep, assiduously, from the age of eighteen or so.

I accepted that I must have forgotten or lost a great deal, but assumed that the memories I did have—especially those that were very vivid, concrete, and circumstantial—were essentially valid and reliable; and it was a shock to me when I found that some of them were not.

A striking example of this, the first that came to my notice, arose in relation to the two bomb incidents that I described in Uncle Tungsten, both of which occurred in the winter of 1940–1941, when London was bombarded in the Blitz:

One night, a thousand-pound bomb fell into the garden next to ours, but fortunately it failed to explode. All of us, the entire street, it seemed, crept away that night (my family to a cousin’s flat)—many of us in our pajamas—walking as softly as we could (might vibration set the thing off?). The streets were pitch dark, for the blackout was in force, and we all carried electric torches dimmed with red crêpe paper. We had no idea if our houses would still be standing in the morning.

On another occasion, an incendiary bomb, a thermite bomb, fell behind our house and burned with a terrible, white-hot heat. My father had…