A leading business expert shows why expertise really matters, and how leaders who deeply understand the nuts and bolts of their industry and organization-- from businesses, to hospitals, to universities, to sports-- make all the difference for its success and the happiness of people who work there. Amanda Goodall has spent a decade researching what makes organizations tick, everywhere from the business world to hospitals and healthcare systems, football and basketball teams, and Formula 1 organizations. By debunking the cult of managerialism (the notion that smart people can run anything and the emphasis on leadership personality), Goodall reshapes our understanding of bosses and the traits necessary for organizational success. She identifies the key characteristics of expert leaders and provides a real and grossly underappreciated model for career success: "go deep into a business, work hard, pay attention, and know your stuff." Those who run hospitals and healthcare systems, for example, should be physicians with deep clinical expertise, not financiers or people parachuted in from other industries. Those who run school systems and universities need to understand from experience the stress of balancing teaching, research, and student welfareCredible demonstrates categorically that expertise matters more than ever and that we need our leaders to be experts with a deep, understanding of their organizations from many years spent learning the business and working their way up the ladder. The people who work for them are happier because they feel better understood and the organizations they lead are more successful.