A company has only one peerless role: chief executive officer. It's the most powerful and sought-after title in business, more exciting, rewarding, and influential than any other. What the CEO controls-the company's biggest moves-accounts for 45 percent of a company's performance. Despite the luster of the role, serving as a CEO can be all-consuming, lonely, and stressful. Just three in five newly appointed CEOs live up to performance expectations in their first 18 months on the job. The high standards and broad expectations of directors, shareholders, customers, and employees create an environment of relentless scrutiny in which one move can dramatically make or derail an accomplished career.For all the scrutiny of the CEO's role, though, little is solidly understood about what CEOs really do to excel. McKinsey's longtime leader, Marvin Bower, considered the CEO's job so specialized that he felt executives could prepare for the post only by holding it. Many of the CEOs we've worked with have expressed similar views. In their experience, even asking other CEOs how to approach the job doesn't help, because suggestions vary greatly once they go.....