Here are a subset of the ideas that are presented in the book,
He says that in complex systems, other than the logical apparatus (eg- the analytical part of our brain), other stressors also give information.
That is why there needs to be some (not a lot) randomness in the system to allow it to collect information through the stressors and evolve.
Here he talks about the stability induced by inhibiting randomness and depending only on the logical apparatus in the system (one example being centralizing socio-economic systems).
He says that there is less fluctuation in stability of the complex systems this way but the lack of information through the stressors catches up with the complex system and causes a sudden collapse.
Here he talks about how Naive-intervention (which is almost always the case with intervention in the complex systems because well they are complex) actually hurts the system rather than doing any good.
There are many other ideas about complex systems that he talks about in the book. In my opinion the book is a must read! It provides us with a perspective that is never talked about since the people (especially policy makers) always naively-intervene and think that what they know is all there is.