O n a brisk spring morning in March 1975, Chris Bazlinton, a tall, fair-haired, bespectacled 27-year-old, arrived at Baker Street station in central London. He’d travelled from his home in Essex in the hope of getting a job at Abbey National, a British building society. The interview went well: he was offered the public-relations role on the spot. “Oh, one more little thing,” the general manager said. “You will also have to act as secretary to Sherlock Holmes, answering the mail that comes in for him.” He paused, with a slight smile: “How do you feel about that?” The Economist today Handpicked stories, in your inbox A daily newsletter with the best of our journalism Sign up Bazlinton thought his new boss might be joking, but grinned back. “I’d be happy to,” he said. As Bazlinton would soon discover, the peculiar position of Sherlock Holmes’s secretary had been created more than four decades earlier, in 1932, when Abbey opened its grand, white-marbled headquarters on Baker Street. The art-deco building was so large that it had been assigned ten street numbers, from 219 to 229. Overnight, one of the most famous literary addresses in history – 221b Baker Street, home of…