The Swedish medical professor Hans Rosling rose to world fame by asking simple questions about the state of health, education, and welfare in the world and demonstrating that most respondents were much too pessimistic and that on the whole we do not match the precision of the proverbial dart-throwing chimpanzee. In this book, he sums up his optimistic view of world development, suggests ten reasons why all of us and even experts tend to be overly pessimistic, and outlines ways we can overcome these hurdles to a more realistic worldview: Avoid dividing the world into us and them or rich and poor but realize that most people are in the middle! Beware of overemphasizing short-term negative news when the long-term shows a gradual improvement! Do not assume that all trends can be extrapolated in a linear fashion! Act on the basis of a risk assessment and not out of panic! Shun the tendency to view groups as uniform when in fact they are likely to be quite diverse! Look for causes not villains! Take a deep breath and insist on seeing the data before you act! And so on! Rosling’s book cannot completely replace his famous bubble charts, but fortunately his Ted talks are still available online. The book supplies a more sustained argument and a detailed list of sources. Hans Rosling died before the book was fully completed but his two co-authors have made it into a coherent text, a compelling argument for a fact-based view of the world, as well as a moving tribute to an academic who became a world-wide educator.