I enjoyed this book. The book develops the premise that crowds, under the right circumstances, can make extraordinarily good decisions. He make a number of studies showing the average of all people’s inputs is surprisingly more accurate than the best member of the crowd. He also touches on when this crowd wisdom breaks down, citing such occasions as the stock market bubble, housing bubbles, and mob rule. The breakdown of crowd wisdom is only touched on, and if I have one complaint about the book, its that this is an important aspect of crowd wisdom and deserves more attention.