Tribes, clans, and extended families affect — positively and negatively, overtly and subtly — the social systems of the countries and regions of which they are a part. We identify areas and issues for deeper focus and provide examples from contemporary Middle Eastern and other societies in which tribes significantly or uniquely impact the social and political order. Tribes, the idea of tribe, and public genealogies of the elite, sometimes considered vestiges of earlier social orders of declining importance, have adapted to modern social conditions and have far-reaching implications.