The following version of this book was used to create the guide: Piketty, Thomas. Capital in the Twenty-First Century. Belknap Harvard, 2014.

Piketty's book studies the history of wealth inequality and distribution from as far back as the eighteenth century. It is divided into four parts, each one addressing a facet of his theme. Each part is meant to elaborate on the one that preceded it. The study moves from analyzing basic concepts for understanding wealth inequality, to their historical study, and finally to their present day social and political impact. The final section addresses some policy choices that could effectively stem rising wealth inequality in the twenty-first century.

Part one lays out some basic parameters for the study of capital and income. In these chapters, Piketty explains, in terms comprehensible to a general audience, certain basic accounting definitions for GDP and national income, his definition of the word "capital," and ways of understanding demographic growth. He also explains the analytical concepts such as cumulative growth, and the idea of orders of magnitude, which are essential for understanding the data that is presented throughout the entirety of the book.

Part two studies the dynamics of the capital/income ratio. Piketty combines the concepts and definitions that he introduced in part one in order derive the capital/income ratio, which plays a key role in many of Piketty's analyses. The importance of the "dynamics" of this ratio leads Piketty to interpret historical events, as he looks to explain historical changes in the capital/income ratio across countries in relation to political and social causes. This gives Piketty occasion to discuss the various forms capital has taken over the centuries, as he highlights in particular the shift from a regime of landed capital, to the advent and further development of industrial capital in our own day. Piketty ends part two by decomposing the capital/income ratio into the capital-labor split. From here he segues into his general theme of inequality.

Part three addresses the topic of wealth and income inequality, along with relevant social contexts and cultural values. Here Piketty analyzes separately inequality in income from labor, and inequality of capital ownership. In either case, Piketty traces the historical events and prevailing ideologies that have led to the concentration of labor income and wealth within the top decile of society. It is shown how prevailing forces of divergence will continue to further concentrate wealth and income at the very highest strata of society. We learn from this section how meritocratic values and the practice of inheritance increase inequality, as well as justifies it. From here, he places inequality in a global context and introduces the urgent need for countermeasures against it on a global scale.

Part four advances concrete and practical policy measures that would likely combat the rise of inequality if implemented. In order to frame these measures, Piketty examines the rise of the social state in the twentieth century and its underlying political justification. He then proposes different ways in which the social state can be modernized to tackle the global democratic interest in greater equality. This ultimately leads to Piketty laying out his plan for a progressive global tax on capital, and ways to manage public debt under such a scheme.

The conclusion ends with the comparatively more modest call for increased participation among economists and social scientists in public debate, emphasizing the key role that democratic consensus will play in the effort to reduce inequality.