Hoover only agreed to take on the job on condition that there would be no political meddling and that he’d be in sole control. He promptly fired around a quarter of all agents and instigated mandatory training for the ones who remained. He enforced strict rules of conduct - agents had to wear white shirts and black wing-tip shoes, and to be as courteous as they were efficient. For reasons no one seems able to explain, he also forbade the drinking of coffee at work after 8.15 in the morning.