Now in 2024, Fortune is launching the 100 Most Powerful People in Business. But how do you measure power, exactly? Revenue alone doesn’t define it, nor does seniority. Who is more powerful: the CEO who oversees a $20 billion enterprise? Or the AI genius who leaves that bureaucratic behemoth to found a nimble, paradigm-shifting startup? The farsighted venture capitalist who inks a term sheet to fund said startup? Or the feared short-seller who bets against the aging tech giant and forces out the CEO? The answer varies from day to day. Power is nuanced. It’s hard-won and easily lost. It’s never static.

That we all know. The question then becomes, how do you distill the vague notions of influence and charisma and sway into something that can be measured? Fortune’s editors scored each candidate on the following metrics:

• Size of the business the person runs, based on our screen that factors in mid-term
  (three-year) and short-term (past 12 months) revenue and profit growth, profitability,
  and market value.
• Health of the business, based on trailing 12-month measures of liquidity, operating efficiency, and solvency.
• Innovation: Has the person accomplished something nobody else has and that
  competitors followed?
• Influence: How greatly do their words and actions shape the behavior of others?
• Trajectory: Where is the person in the arc of their career?
• Impact: Is this person using their power to make the world a better place?

What you’ll find on this list: leaders from 40 industries, ranging in age from their 30s to their 90s. You’ll come across very recognizable founders, chief executives of great businesses, disrupters, and innovators. What you won’t find: fossilized billionaires who are no longer active in business; nor will you find politicians, regulators, or seconds-in-command. (For our purposes, having a boss in the C-suite was a check on one’s power that usually excluded you. A few exceptions include companies like Blackstone and Berkshire Hathaway where a succession plan is well underway.)

In the end, the people who earned places on the Most Powerful People list share a vital trait: Their words, deeds, and wealth shape what others around them think and do. They might exercise their power by shouting in headlines, or via subtle nudges behind closed doors. They might, like Elon Musk, have essentially invented industries where none existed before. They might, like Jensen Huang, have built a company so central to the health and trajectory of other businesses that most CEOs would take his call before the president’s. They might, like Satya Nadella or Mary Barra, have breathed new, urgent life into huge companies that were in danger of stagnation. They might, like Mellody Hobson, have the behind-the-scenes clout to oust struggling CEOs and handpick new ones. They might, like Sam Altman, have developed a technology so astonishing that virtually every other business leader in the world is reacting to their invention.

John D. Rockefeller once said, “If your only goal is to become rich, you will never achieve it.” We would submit that the same could be said of power. Those who nakedly seek it rarely possess it for long. Those who have it? Well, they’ve earned a spot—at least for this year.

This article appears in the December 2024/January 2025 issue of Fortune.