Booksellers say that books are a cheap form of entertainment. For the price of a film ticket you can buy a paperback that will divert you for much longer. The film “Doctor Zhivago” is a little longer than three hours. The novel will provide you with more than 12 hours of fun, if you read at an average speed. But you can also use that argument against reading. In terms of time, books are expensive. A so-so book can waste all your leisure time for a month.

That hasn’t stopped me from reading books. But now that I’m of pensionable age I’m pickier. I suspect that I’ll find our new interactive listing of the “greatest books of all time” useful in deciding what to read. It provides a searchable ranking of 500 books that appear often on best-books lists, and tells you how long it would take you to read each one. (That’s how I found out that Boris Pasternak’s romantic epic takes half a day to read.)

I wouldn’t take the ranking as gospel. These days I find it more rewarding to read books that have been around for a few centuries than those that have appeared in the past few decades, excellent though some of them are. Thankfully, many of the old classics make the top 500 (you can search by decade or century of publication). Spend your tome time wisely.