The book discusses the ideas of "sustaining technology" vs. "disruptive technology" and describes with many examples how disruptive technology advances have a very strong negative effect on large established businesses. In general I thought the argument was well laid out and informative. My only complaint is that I would have liked to hear a more balanced argument. The authors did not spend significant time looking at any counter examples to their arguments. It felt a little like the authors first came up with a theory and then went out looking for specific examples to support this theory, instead of a more objective approach that would include relevant counter examples.