This Special Issue is the condensation of an author-meets-critics double panel organized for the African Studies Association meeting in Washington, D.C., in November 2005, on Jane Guyer's challenging book Marginal Gains—Monetary Transactions in Atlantic Africa. The book was published in the first half of 2004, and when the three of us met in the fall of that year, we all felt it was a text that lent itself especially well to such a session. One of the elements that makes the book so compelling is Guyer's particular style of theorizing: Starting from a painstaking effort to discover regular patterns in empirical data, she moves to the positing and testing of theoretical notions—but in a way that does not strive to produce closure or systematicity. On the contrary, the book can sometimes be confusing because it leaves so much open. But precisely because Guyer continues to create new openings, it is an inspiring piece of work, constantly offering novel starting points for further research and reflection.