Thomas Piketty studies the history of human inequality, examining the processes that shaped the modern world. In his book, he emphasizes that despite crises and disasters, history provides grounds for optimism. Piketty analyzes the impact of capitalism, revolutions, imperialism, slavery, wars, and the building of a welfare state. He also notes that, despite violence and social struggle, societies gradually moved toward a more fair distribution of income, reduced racial and gender inequality, and expanded access to healthcare, education, and civil rights.