The book examines the problems of local self-government reform in Ukraine during the period of martial law. The internal focus is on the process of decentralization, which includes all levels of implementation of governmental powers and public initiatives. The external focus is on European integration as defined in the Constitution of Ukraine. The relevance of the research is evidenced by the systemic changes in Ukraine’s domestic and foreign policy, the processes of decentralization and European integration, as well as the challenges associated with the active phase of Russian aggression. It is argued that a comprehensive political and legal framework needs to be established in order to exploit the potential of the institution of local self-government. The book concludes by emphasizing that the processes of European integration and decentralization of power during the period of martial law represents a priority of the modern state-building phase of Ukraine.