Since its ancient origin in Aristotle's Politics, the idea of the middle class has had three major boom periods, with periods of marginalization in between. The first was during the early nineteenth century in Europe. The middle class was the first explicit class, and it was hailed as a rising actor, against the aristocracy and monarchical absolutism, and as carrier of the new ideology of liberalism. Then followed a long decline, when the middle class was overshadowed in the global North by the worker question, the working class, and the labor movement, and in the South by the colonial question and anti-imperialism. After World War II the idea had a triumphant return, but largely confined to the United States, where it came to eclipse the working class in public discourse.The third boom, which began in the twenty-first century and currently seems to be ebbing, had its center in the global South, whence continental development banks and international organizations sent out reports on middle-class prosperity and growth into the demographic majority. Southern political leaders—from Brazil's two left-of-center presidents, Luiz Inácio Lula da Silva and Dilma Rousseff, to Vietnam's deputy prime minister Hoang Trung Hai—proudly announced the arrival of the middle class. After some resistance the notion was accepted in China after 2000, as a force of social stability. In the North too, there was a revival of interest in the middle class, but as part of lamentations of its decline or destruction.The Middle Classes in Latin America is part of the third middle-class boom, with some academic lag. It shares much of the post-nineteenth-century middle-class boom mood, uninterested in inequality, capitalism, social conflict, and protests, comfortable in the status quo, preoccupied with being modern, self-centered, and interested in social climbing and distantiation. There is no self-reflexivity, despite the fact that one of the editors, A. Ricardo López-Pedreros (in his introduction), and one author, David Parker, deal extensively with middle-class historiography and sociology. Nor does self-reflexivity appear in Barbara Weinstein's engaging but surprisingly little explicitly evidenced plaidoyer for a middle-class interpretation of São Paulo, launched from a critique of neglect of the middle class in previous treatments.However, geohistorical context—in this case, postrevolutionary, postindustrial, still aspirationally modernist Latin America—might illuminate but by no means define a work of scholarship. This is a work of very interesting scholarship, and your reviewer, a global sociologist rather than a Latin Americanist historian, read it with fascination—in spite of its format. The collection stems from a conference and has 24 contributions without any systematicity and connectedness, although they are given some order by active editing. Its sprawling size makes a fair review of individual contributions impossible. Its strengths are discourse analysis and ethnography, its wide national range (covering seven individual countries, from overrepresented Mexico to Brazil and Argentina), and its methodological and theoretical contributions to middle-class investigations from Latin American experiences, primarily in the introduction by López-Pedreros and the essay by Parker.The critiques of theories lionizing the middle class (modernization theory) as well as those neglecting it (Marxism, dependency theory, subaltern studies, postcolonial theory) hit their targets, to varying extent. But the remedy proposed is a historian's abstention from theoretical development: only “to question the binary understanding,” as López-Pedreros puts it (p. 18), or to let different approaches talk to each other, as Parker argues (p. 399). A book with The Middle Classes in the title could do better than that.Because of its tensions between, on one hand, social and economic heterogeneity and ambiguity and, on the other, an assertive ideological essentialism—as carrier of reason, moderation, democracy, and so-called sound economics—the middle class is an exciting scholarly subject, particularly in times, like today, hung up between social stasis and social catastrophe.There are, at least, two sets of intriguing questions, one referring to the Aristotelian idea of social middleness, the other to the modern idea of the middle class in different cultures and societies. What does social middleness mean in different cultures and societies with their hierarchies, in terms of characteristics and in terms of distance? What does middleness mean and look like in economic terms? To what extent and how has there been a middle-class formation in different modern societies? What role, contemporarily perceived or as found by today's historians, did the middle class play in nation formation? How significant has the middle class been as a political interpellation across times and societies, in relation to competing others—the poor, the working class, workers, and the people, to name some? How does the middle class operate as personal aspiration or differentiation, and as social force?This is a book of its time and place, illuminating them from many angles and raising a number of challenging questions without formulating them.