The book, Sum: Forty Tales from the Afterlives, has also stormed to number two on bestsellers list, thanks largely to the positive recommendations from the comedian and writer on his site. The book, a collection of stories about the afterlife, offers 40 brief scenarios for what happens when you die. Fry tweeted: “You will not read a more dazzling book this year than David Eagleman’s “Sum”. If you read it and aren’t enchanted I will eat 40 hats.” Figures from online bookseller, Amazon.co.uk, show after Fry’s “tweets” the title climbed to the number two spot on the its bestsellers list. It rose from number 3,629 on the list, with sales jumping by about 6000 per cent. “We have seen spikes in sales before as a result of activity on Twitter but nothing as significant as the uplift we have seen on the back of Stephen Fry’s recommendation,” said Amy Worth, head of books buying at Amazon.co.uk.