Although strategy today is a demanding, complex, and subtle discipline, you would never know that from reading the management journals and business best-sellers of the past five years. Each season brings a new crop of experts proclaiming that their frameworks—core competencies, customer retention, management ecosystems, strategic intent, time-based competition, total quality management, "white spaces," managing chaos, value migration—are definitive. These solutions sometimes prove an exquisite fit, but just as often they offer only a mediocre approximation.

Nonetheless, managers reach out to these new theories because the classical microeconomics-based model of strategy is inadequate in a growing number of situations. Consider some recent examples:

• A telco executive must make a $1 billion "yes or no" decision on whether to invest in a new network technology to provide new services to customers. One best-practice market research survey predicts a return on investment of 25 percent; a second, equally valid, forecasts minus 25 percent. What should that executive do?
• How should executives at a software firm deal with a large customer that is also the firm's chief competitor—and one of its biggest suppliers?
• How should the chief executive officer of a credit card company think strategically about positioning when segments and value...