In 1936 Dale Carnegie wrote How To Win Friends and Influence People. And with that he started an entire industry. What began as a succession of how-to books on various matters has now proliferated into videos, training programmes, workshops, portals, apps and even whole companies devoted to the subject. But more than just creating the industry, Carnegie also gave it its name—‘How To’—which David Ogilvy, that shrewd manipulator of people, called one of the most powerful phrases in the language.