Zanzibar Was a Country traces the history of a Swahili-speaking Arab diaspora from East Africa to Oman. In Oman today, whole communities in Muscat speak Swahili, have recent East African roots, and practice forms of sociality associated with the urban culture of the Swahili coast. These "Omani Zanzibaris" offer the most significant contemporary example in the Gulf, as well as in the wider Indian Ocean region, of an Afro-Arab community that maintains a living connection to Africa in a diasporic setting. While they come from all over East Africa, a large number are postrevolution exiles and emigrés from Zanzibar. Their stories provide a framework for the broader transregional entanglements of decolonization in Africa and the Arabian Gulf. Using both vernacular historiography and life histories of men and women from the community, Nathaniel Mathews argues that the traumatic memories of the Zanzibar Revolution of 1964 are important to nation-building on both sides of the Indian Ocean.