With the exception of the Crimean Tatars, the history of Islam in Ukraine, often remains unnoticed. However, traces of Muslim communities have been recorded since the 8th century. Based on materials from private and state archives, as well as interviews with representatives of Muslim communities and state bodies responsible for religious policy, the book reveals the previously unknown history of Muslim communities in Ukraine since the late nineteenth century: first as part of the Russian Empire, then the Soviet Union, and after 1991 in independent Ukraine. It analyzes how Muslims have preserved, transformed, and passed on their religious identity through formal, informal, and often underground structures. The history of these communities shows that institutionalized Islam has existed in Ukraine since the late nineteenth century, even though after 1951 it was unofficial and even underground. In independent Ukraine, the institutionalization of Islam included the emergence of Volga Tatar communities from underground, the registration of Crimean Tatar communities returning from deportation, and the emergence of communities linked to transnational Sufi and Islamist networks.