In the ancient Greece of Pericles and Plato, the polis, or city-state, reigned supreme, but by the time of Alexander, nearly half of the mainland Greek city-states had surrendered part of their autonomy to join the larger political entities called koina. In the first book in fifty years to tackle the rise of these so-called Greek federal states, Emily Mackil charts a complex, fascinating map of how shared religious practices and long-standing...