I do not recommend this book. Although, Mr. Ray Dalio repeatedly states all the research he has done there are no citations and there is no bibliography. The main theory behind the stages of cycles that States go through is highly questionable. For example, States that are in the peak of their cycle have more income distribution. Great Britain in the nineteenth century or most European states at their peaks had very little distribution in wealth and income. In fact, Marx thought this made them vulnerable to revolution. Dalio does claim revolution is more likely when income distribution is at its worst but that is one of Marx’s arguments that did not materialize. Mr. Dalio has an ascending looping line to describe his theory of evolution, which he relates to “civilization.” He even describes evolution as a continuing theory of improving. He would of course get this wrong in a high school biology class. I would recommend David Graeber and David Wengrow’s The Dawn of Everything: A New History of Humanity for a better understanding of the non linear progression of urban human development. I would also recommend Thomas Piketty’s Capital in the Twenty-First Century for a better understanding of State’s development and income and inequality impacts on States.