A lot of factors have contributed to American inequality: slavery, economic policy, technological change, the power of lobbying, globalization, and so on. In their wake, what’s left?

That’s the question at the heart of a new book, The Vanishing Middle Class: Prejudice and Power in a Dual Economy, by Peter Temin, an economist from MIT. Temin argues that, following decades of growing inequality, America is now left with what is more or less a two-class system: One small, predominantly white upper class that wields a disproportionate share of money, power, and political influence and a much larger, minority-heavy (but still mostly white) lower class that is all too frequently subject to the first group’s whims.