NEW YORK (Fortune) -- For two decades, the management philosophy of ex-GE CEO Jack Welch has been the holy grail of business practice.

Now, globalization, market volatility and the flood of new, disruptive technologies are forcing changes in both practice and mindset. Recently, Fortune talked to four influential CEO's, plus Jack Welch himself, about what's different about running a business today.

Their answers, about everything from the importance of market share to the role of shareholders, may surprise you.

For a photo gallery and their comments, click on the links below.

• John Chambers, CEO, Cisco (Charts)

• Neville Isdell, CEO, Coke (Charts)

• Art Levinson, CEO, Genentech (Charts)

• Anne Mulcahy, CEO, Xerox (Charts)

• Jack Welch, retired CEO, GE (Charts)