 they can care for their families, to give their share- owners a fair return on their investment, and to help build a civil society. Running a business isn't about creating short-term trading value, it's about building a long-lasting institution. Corporations are such a relatively new institution-only a few hundred years old in their current form-that we tend to forget this. Many people think that the primary reason to incorporate is to limit liability, and, in our litigious society, that is indeed an advantage. But Blackstone's Commentaries on the Laws of England, which codified English common law for the first time in 1758, explained that corpora- tions were devised because "personal rights die with the person" and "investing a series of individuals, one after another, with the same identical rights, would be very inconvenient, if not impractical." Cor- porations are "artificial persons" who enjoy "a kind of legal immortal- ity." Indeed, Blackstone listed "to have perpetual succession" as the Practice Ambidextrous Leadership very first of a corporation's "rights and capacities" and "the very end of its incorporation." Not every company is worthy of such immortality. The average life cycle for a public company is only forty years. Those that endure are those that have found a way to balance the legitimate interests of all their stakeholders: employees, customers, investors, and the commu- nities in which they live and work. But that requires a standard of ambidextrous leadership that not many managers have mastered. It means addressing the legitimate interests of multiple stakeholders, not sequentially, but simultaneously. F. Scott Fitzgerald said, "The test of a first-rate intelligence is the ability to hold two opposed ideas in the mind at the same time and still be able to function." Great companies demonstrate that kind of intelligence by treating profit and stakeholder goals as complemen- tary, not contradictory. AT&T was once such a company. Lessons of the Past There are two reasons to remember the past. A