The year 1859 was a big one for British publishing. Charles Darwin’s On the Origin of Species was published, as was John Stuart Mill’s On Liberty. So too was a now largely forgotten book by an author named Samuel Smiles. It was boring, badly written and critically panned: one writer called books of its sort “the silliest ever known”. Naturally, readers loved it.

It outsold Darwin, popularised a new term and in the process changed publishing for ever. It was called Self-Help and its aim was simple: to teach readers that “with Will one can do anything”. One could certainly sell more books: last year in Britain, according to figures from Nielsen BookData, 3 per cent of all books sold were self-help.