This book is based on the same research as How to be a Star at Work.  There is quite a bit of hyperbole in the beginning that seemed like standard journalism – taking an outlier and suggesting it supports the writer’s hypothesis.  Things got better in the section on research on expertise.  The author collates several studies that confirm that particular fields have “a number,” that is, a number of years of hard intense study that it takes to be a ranked expert in that field.  What they find is that “child prodigies” such as Mozart or Tiger Woods had father’s that were teachers, and they started learning before age 5.  So by the age of 17, they had over 10 years of experience.  And even then, Mozart’s best work was years latter.  Also among research findings was the concept of deliberate practice – that practice on things you are not good at, that to you “are hard,” is what separates experts from the tier below.  The author’s try to extrapolate the concept of deliberate practice to management and leadership – this section feels rather hollow.