What is the theme in The Black Swan: The Impact of the Highly Improbable by Nassim Nicholas Taleb?

Unpredictability is a theme in this book. Over the past few centuries, many attempts have been made to predict various events. The author argued that most of these attempts resulted in wrong predictions, and if they were right, it was not due to having built a reliable prediction technique. Over all this time, people had been fooling themselves. The condition became worse with computerized spreadsheets and other modeling programs. What actually characterized the world was a high level of unpredictability.