To quote a friend, “I thought about dressing up as a credit default swap for Halloween, but it just got too complicated.” Most of us are struggling to wrap our minds around the peculiar debt products that helped usher in the current economic crisis. In her new book, Payback: Debt and the Shadow Side of Wealth, Margaret Atwood steps back — how did we come up with the notion of debt in the first place? The book is the text of the 2008 Massey Lecture, an annual Canadian event in which a noted thinker holds forth on a topic. (Past lecturers have included Martin Luther King Jr., John Kenneth Galbraith, and Doris Lessing.) Atwood spends a large portion of her inquiry in literature but draws in contemporary examples, sociology, and political science. The book is full of delightful rabbit holes; in the chapter on debt as plot, for example, we’re given a short disquisition on the role of mills in literature. Of trickle-down economics, Atwood — ever the novelist — writes, “Notice that the metaphor is not that of a gushing waterfall but of a leaking tap: even the most optimistic endorsers of this concept do not picture very much real flow, as their language reveals.” In the final chapter Atwood reimagines Dickens’s Scrooge considering the wrecks of modern capitalism. It’s the collection’s weak point: one wishes she’d either have taken the full plunge into fiction or kept to her arch academic tone. But as a whole, the book is a useful tour of the meaning of debt in modern society.