How do you choose a book?

How do you choose which books to read? I have two main means of doing so: recommendations from people I know and reviews in the newspapers and magazines I read. Since these latter are chiefly the Financial Times and the Economist (for work reasons), I tend to end up reading a fair number of heavy factual books.

I try to alternate between fiction and non-fiction. For fiction, I am disinclined to waste time reading books that have not earned the respect and affection of those millions of readers who have gone before me. If you can read a book by an undisputed genius like Dickens or Hemingway, why take the risk of trying a writer lacking in similarly large quantities of unsolicited testimonials, in the form of cross references and adaptations?

I do read new and experimental writers. But if something is not very good, I will give up. I used to believe this was vaguely immoral, that there was something self-improving about reaching the end even of a book I was not enjoying very much. But age brings wisdom and life is too short. Unless you know from years of positive comment that a book contains something to make it worth persisting with, if you don't like it - drop it.