“When Arthur Conan Doyle created the iconic Sherlock Holmes in 1887, he had no idea that his readers would come to think that the investigating detective really existed. But that is what happened: thousands of readers wrote to Sherlock Holmes at 221b Baker Street, asking him to solve an astonishing array of cases. Doyle also received letters full of riddles and unsolved crimes, as everybody believed that someone capable of solving the most difficult fictional crimes would also have the intelligence to solve them in real life. And they were not far from the truth, because Doyle did solve many real cases in the course of his life.”