Why this book
Banerjee and Duflo wrote this book after winning global attention (and, months after publication, the Nobel Prize) for using randomized controlled trials to test development interventions directly on the ground, rather than reasoning from economic theory alone. Here they turn that same evidence-first instinct on the biggest political arguments of the moment: does immigration lower native wages the way both restrictionist politicians and textbook supply-and-demand models predict? Does free trade's aggregate benefit actually reach the workers whose factories close because of it? Is GDP growth something economists actually know how to reliably produce, or is that expertise mostly theater? Chapter by chapter they show that the honest empirical answer to each question is more complicated, and often more humane, than either standard-issue free-market economics or its populist critics assume — migrants tend to raise, not depress, local wages and economic activity in the destination communities studied; trade's gains are real in aggregate but concentrated painfully among displaced workers who don't relocate or retrain nearly as easily as trade models assume; and the mechanisms that produce sustained national growth are far less understood, even by expert economists, than the confidence of growth-focused policy debates would suggest.
The book's real argument, though, is less about any single policy conclusion and more about a habit of mind: that economists have too often let elegant, simplifying assumptions about how people behave — that they'll move for a better job, retrain for a new industry, respond rationally to a subsidy — stand in for what people actually do, which is shaped by identity, dignity, social ties, and aversion to loss in ways theory tends to flatten out. Their proposed corrective leans on behavioral economics and their own trademark method, randomized trials that test what actually happens rather than what a model predicts should happen, and it leads them toward policy conclusions (carbon taxes paired with direct redistribution, more generous and less punitive social safety nets, skepticism that growth alone should be the overriding policy goal) that don't map neatly onto either party's existing platform.
Who should read it
Readers exhausted by both free-market certainty and its populist opposite, who want an economics book willing to say "the data on this is more mixed than either side admits," will find this refreshingly honest. It's also valuable for anyone trying to understand what economists actually know, versus merely assume, about migration, trade, and growth. It will frustrate readers looking for a tidy ideological home — free-market economists will object to its skepticism about trade's net benefits and growth-centric policy, while some on the left will find its empirical caution about big, ambitious redistributive claims (it insists on evidence over aspiration even for policies it's sympathetic to) too restrained.
About the author
Abhijit V. Banerjee and Esther Duflo are married economists and professors at MIT who jointly won the 2019 Nobel Memorial Prize in Economic Sciences, shared with Michael Kremer, for their experimental, randomized-controlled-trial approach to studying global poverty. Banerjee, born in Mumbai, earned his PhD at Harvard; Duflo, French-born, also completed her doctorate there. Their prior book, Poor Economics (2011), established the same evidence-driven method applied specifically to poverty alleviation in developing countries.