Microsoft is the reigning powerhouse of computing, and Google is the muscular Internet challenger. On each side, the battalions are arrayed – executives, engineers, marketers, lawyers and lobbyists. The spending and rhetoric are escalating, as the realms of desktop computing and Internet services and software overlap more and more.

For each, it seems, the other passes what Andrew Grove, a founder and former chairman of Intel, calls the “silver bullet test” of strategic competition: “If you had one bullet, who would you shoot with it?”

Business historians and management experts say the experience in two of the defining industries of the 20th century, mass-market retailing and automobiles, may well be instructive. The winners certainly scored higher in the generic virtues of business management: innovation, execution and leadership.

But perhaps even more significantly, those who came out on top, judging from U.S. corporate history, had two more specific attributes. They were the companies, according to business historians, that proved able to adapt to change instead of being prisoners of past success. And in their glory days, these corporate champions were magnets for the best and brightest people.

“One area where Microsoft and Google are really competing head-to- head now is in the war for talent,” said Richard Tedlow, a historian and professor at Harvard Business School. “Historically, the company that won the war for talent won the war.”

Which side are you on?