Whenever I talk to people about biography (which is as often as they will let me), they always say roughly the same thing. ‘When I was young, I never read biography – it was fiction, fiction, fiction. But not any more. I don’t know if it’s fiction that’s changed or me, but all I want to read now is biography.’

Biographers shouldn’t use anecdotal evidence. But though my sample is small, its direction is overwhelmingly one-way. I stand by my findings, therefore. Young readers prefer fiction to biography; but as they get older, their preference reverses. 

That is good news for biographers, since the only certain thing besides death and taxes is ageing. But birth is unlikely to go completely out of fashion either, so we needn’t worry about our novelist friends. We can sit back on an idle summer’s day and ask: Why?