With the book The Wisdom of Crowds James Surowiecki wrote a fantastic book on the topic why crowds of people can come to interesting decisions in certain situations. Recently crowd reviews, also known as collaborative filtering got quite popular with the appearance of recommendation engines that support customers in deciding which product to choose. Surowiecki explains, by using fascinating historic stories, in which situations crowds were able to solve complex problems. He also highlights how the stock market, as a huge global crowd of trading people, is able to predict the value of businesses and even the outcome of judicial investigations, such as the investigation that followed the Challenger desaster in 1986. The Wisdom of Crowds describes in detail which kind of problems can be solved by using crowd decisions as well as the criteria which define specific situations in which the result of crowd decisions can lead to reasonable results.
With The Wisdom of Crowds James Surowiecki wrote a solid book that explains the dynamics of crowd based decision making by using entertaining stories on each of the highlighted aspects.