Writers, especially those early in their writing career, can improve their books with a straightforward self-check. The best books tend to have a high density of significance. By this rather fancy sounding term I mean the numerical ratio of sentences to significant realisations. Let me explain.

On the least dense end of the scale you might find a self-published genre novel that has one significant thought per page. Anyone reading that page gets little more from it than, say, the fact that the ...