Rare indeed are chief executives who don't launch at least one major organizational transformation during their tenure—to catch up with other companies, to recover from a crisis, to get the best from an acquisition or a merger, or just to stay on top. In today's business environment, incremental improvement is seldom enough.

But for all that has been written about change, no one formula can make it successful. The most important factor is often a CEO's ability to create, sustain, and channel the organization's energy. Releasing it requires broad-based action: creating the right architecture for the change program, emphasizing both near-term performance and longer-term health, setting the right aspirations and creating a time line to meet them, embedding change in processes and systems, transforming the behavior of employees, and renewing the senior-management team. This is indeed no small challenge—no other kind of effort requires such strong leadership from the top to make the right impact.

As part of The McKinsey Quarterly's efforts to understand the process of corporate transformation, we have talked with a number of successful executives in the past year or so about their experiences and insights. A complete listing of these interviews are available on our...