Few even well-informed business leaders seem to recognize Visa as the largest business organization in the world, despite a turnover that is some 10 times that of Wal-Mart and a market value that is, conservatively speaking, more than double that of General Electric. I have often wondered why this is so. How could the world's largest business also be one of the business world's best kept secrets? It is certainly not that its product is little known, nor that it is the leader of an obscure industry. There are few companies that could claim that one-sixth of the world's people were its customers last year! Yet, over the past decade, there have been well over a thousand feature articles in Business Week, Fortune, and Forbes on Microsoft, over 350 on GE, and about 35 on Visa ---- Foreword