Hans Rosling was one of my best teachers. He was always kind, often patient, and never judgmental. He spent his life not only understanding how global health was improving but sharing what he learned in a fun, clear way. If you never met Hans or watched one of his many TED talks, his new book will help you get a sense of why he was so special. I just wish I could tell Hans how much I liked it. “Factfulness” is a fantastic book, and I hope a lot of people read it.