Replying to our Christmas 'good guru guide', Peter Drunker, the grand old man of management theory, speculated that the word 'guru' had become popular only because 'charlatan' was too long a word for most headlines. Few people are easier to ridicule than management gums. Irrepressible self-publicists and slavish fashion-merchants, they make a splendid living out of recycling other people's ideas ('chaos management'), coining euphemisms ('downsizing') and laboring the obvious ('managing by wandering around' or the customer is king'). Their books draw heavily on particular case studies—often out-of-date ones that have nasty knack of collapsing later. And their ideas change quickly. Tom Peters, once a self-confessed sycophant to the corporate behemoth, is now an apostle of the small, chaotic, 'virtual' organization. Gurus do have their uses, however. Begin with the circumstantial evidence. In America, where management theories are treated with undue reverence, business is bouncing back. In Germany, where business schools hardly exist and management theory is widely seen as an oxymoron, many companies are in trouble. German business magazines are suddenly brimming with articles about 'downsizing' and 'business process re-engineering'. In Japan firms are once again turning to business theories from America—just as their fathers learnt after the Second World War from American quality-control techniques. Coincidence does not prove causation: American firms were just as much in love with gurus when they ware doing badly. But the fact that Germans and Japanese are paying attention again does offer some dues. The most important point in favor of management theories is that they are on the side of change. In 1927 a group of psychologists studying productivity at Western Electric's Hawthorne factory in Illinois found that workers increased their output whenever the level of lighting was changed, up or down. At the very least, theorists can make change easier by identifying problems, acting as scapegoats for managers—or simply making people think. A vested interest in change can lead to faddism. But, taken with a requisite dose of scepticism, it can be fine complacency-shaker. A second argument for gurus relates to knowledge. The best management theorists collect a lot of information about what makes firms successful. This varies from the highly technical, such as how to discount future cash flow, to softer organizational theories. Few would dispute the usefulness of the first. It is in the second area—the land of 'flat hierarchies' and 'multi-functional teams'—that gums have most often stumbled against or contradicted each other. This knowledge is not obviously prodding a strategic recipe for success: there are too many variables in business, and if all competitors used the same recipe it would automatically cease to work. But it does provide something managers want: information about, and understanding of, other companies experience in trying out tactics—thinner management structures, handing power to workers, performance-related pay, or whatever. A good analogy may be with diets. There is no such thing as the 'correct' diet, but it is clear that some foods, in some quantities, axe better for you than others: and it is also likely that the main virtue of following a diet is not what you eat but the fact that it forces you to think about it. If management diets come with a lot of hype and some snake-oil, so be it. Which of the following is the most suitable in meaning for the word 'guru' in the passage?