Much of our business thinking is shaped by delusions - errors of logic and flawed judgments that distort our understanding of the real reasons for a company's performance. In this book, Phil Rosenzweig unmasks the delusions that are commonly found in the corporate world. These delusions affect the business press and academic research, as well as many bestselling books that promise to reveal the secrets of success or the path to greatness. Such books claim to be based on rigorous thinking, but operate mainly at the level of storytelling. They provide comfort and inspiration, but deceive managers about the true nature of business success. The most pervasive delusion is the 'Halo effect'. When a company's sales and profits are up, people often conclude that it has a brilliant strategy, a visionary leader, capable employees, and a superb corporate culture. When performance falters, they conclude that the strategy was wrong, the leader became arrogant, the people were complacent, and the culture was stagnant. In fact, little may have changed - company performance creates a Halo that shapes the way we perceive strategy, leadership, people, culture, and more.