They are the superstars of the corporate firmament. No management conference can be considered complete without their presence. They stride up and down the stage, they wave their hands in the air and the audience hangs on their every word. They are the management gurus - that elite band of theorists who have made fame and fortune from interpreting the practice of business.
Who are the gurus and how do they achieve their exalted status? Mr Peter Drucker, the granddaddy of them all, the founder of management theory, does not even recognise the term, preferring to call himself a journalist or a "bystander", the description he chose in the title of his autobiography.
Mastering contradictions, however, is the guru's art and Mr Drucker knows this. Now approaching 90, he can still enthral audiences, although these days it is mostly by video conferencing link. He owes his fame to the management book: it is difficult to be a guru without one and Mr Drucker has more than 30 to his name.
Mr Warren Bennis, at 76 one of the first big names to emerge in the post-second world war generation of management theorists, has written 18 books, mainly on the subject of leadership. This is another key to gurudom - find your speciality and stick to it. That ensures you become "the expert" on the subject.
Mr Tom Peters has still to make double figures in the publishing count but In Search of Excellence, the book he co-authored with Mr Robert Waterman, was one of the best-selling management books of the 1980s. It sold more than five million copies worldwide and propelled Mr Peters to the top of the most-sought-after guru list during the late 1980s and early 1990s. He can still command speaking fees approaching $100,000.
It was Mr Peters who perfected the arm waving and platform pacing technique - a management version of the gesticulations performed by those other stars of the stage, Elvis Presley and Tom Jones. Mr Peters, more than anyone, introduced the performance element into the guru's art. In doing so, he not only enthused audiences, but increased the fees speakers could command.
Today most of the top gurus arrange their speaking appointments through high-priced agents. "If an agent is involved you are rarely going to get someone for less than $50,000," said a conference organiser.
Another factor deciding conference fees is ability to pay. A large consultancy taking bookings for its annual client conference or a professional body planning a set-piece event for its members is likely to be charged much more than a gathering of business school alumni or a charity, where the guru might waive the fee.
The route to gurudom usually starts with a strong piece of research. The Peters and Waterman book emerged from a research project at McKinsey, the management consultancy, where Mr Peters was principal practice leader on organisational effectiveness and where he first began to establish a reputation as a writer and a speaker.
One feature of In Search of Excellence, again copied many times afterwards, was the use of gimmicky alliteration - the "Seven S" model of organisational variables: structure, strategy, systems, skills, staff, style and shared values.
The importance of the Big Idea for a management guru cannot be overestimated even if, like Mr Peters, you see some of the companies you have held up as examples go down the tubes, or, like Mr James Champy and Mr Michael Hammer, authors of Re-engineering The Corporation, you experience a backlash from those whose enthusiasm for the idea has begun to wane.
Consulting remains an important source of income for some business gurus but most of the 1990s generation have strong academic connections, partly, perhaps, due to the increasing prominence of business schools.
Ms Rosabeth Moss Kanter, for example, combines a professorship at Harvard Business School with consulting and writing. Her background in sociology has enabled her to focus on the people side of business.
Business itself produces the occasional guru. Mr Bill Gates, head of Microsoft, writes books and speaks to conferences - but the influence of business leaders is usually based on their success, not on their philosophy of management.
While business leaders can pass on the secrets of their success to an audience of "wannabees", the gurus' role is to buck conventional wisdom. Mr Drucker was doing this in Concepts of the Corporation, a study of General Motors that told the management some unpalatable truths about the way they ran their company.
The US remains the biggest spawning ground for gurus but other countries such as India are beginning to make an impact. Japan has Mr Kenichi Ohmae and a few other big hitters. Britain has Mr Charles Handy (although he was born in Ireland). Prof Handy, who does not speak as often as he used to, usually gives his fee to charity. He, like many gurus, prefers to tie his speaking tours to a book promotion.
The message might be straightforward, but if the guru can put it over with panache, the rewards can come close to matching the fees of pop stars and sports celebrities. Prof Hamel was paid $100,000 for two 40-minute slots at last year's annual conference of the Institute of Personnel and Development in Harrogate.
Big names like Prof Hamel and Prof Moss Kanter are not necessarily the best value for money, however. Shrewd conference organisers book second-tier gurus, who are not yet so well known.
Mr Sumantra Goshal, from London Business School, and Mr Christopher Bartlett, from Harvard, are examples of rising stars who have graduated from second-tier gurudom. Their book, Managing Across Borders, was a hit with companies seeking to increase their international reach, and they are increasingly popular with conference organisers.
The chances are, however, that the next big idea is just around the corner. Someone, somewhere, is putting the finishing touches to a groundbreaking study, picking the slides, packing the Powerpoint and priming the publisher. The title might even be: "The seven ways to success as a management guru."
