In his essay here, Darrigol takes on the all-too-vexed question of Einstein's relation to the French mathematician, philosopher, and physicist Henri Poincare. It is vexed in the first instance because Einstein and Poincare could not bear to cite each other on relativity theory. As far as we know, they did not once exchange so much as a postcard on the topic; and they had only one meeting, which went rather badly. Tension resulting from this lack of mutual recognition was, in the second instance, greatly exacerbated during the Nazi years when, in Germany and in many of the countries that fell under its domination, Einstein was triply damned: as a Jew, as an internationalist, as an advocate of a new form of physics. Anti-Einstein enthusiasts used Poincare (and the Dutch physicist H. A. Lorentz) to displace Einstein from his own work, to relabel the accomplishment as the relativity theory of Lorentz and Poincare. In the years that followed, the task of sorting out credit, never very productive, has glowed radioactively with the heat of nationalism, anger, revisionism, and righteous indignation. Darrigol rightly wants to leave those debates behind and bring some analytic clarity to the various alternative accounts given of the complex issues surrounding the relation of Einstein to Poincare. With his usual care, he sorts through the two theories, considers the various accounts of their relation to one another, and reminds us how deeply embedded both were in their time and how fully the theory was reworked in the years that followed.