Historical scholarship on Arab nationalism has experienced a conceptual revolution over the last two decades. It is now widely accepted among historians that local identities and loyalties have been crucial components of nationalist thought and action from the very beginning; it is equally well established that the line between nationalism and various elements of Islam is much harder to draw than one might imagine. In addition, there is solid evidence that nationalism across the Arab world took shape, arguably as an unintended consequence, out of sustained interaction among conflicting elite and popular conceptions of political community. Moreover, it turns out to be important to differentiate Arab nationalism as a cluster of ideological principles from Pan-Arabism as a set of diplomatic practices that constituted a basic component of regional statecraft, initially at the time the Ottoman Empire found itself disintegrating and later on as the newly independent states of the Middle East and North Africa experimented with ways to get along simultaneously with one another and with outside powers.