This book collects nine articles that originally appeared in the journal Harvard Ukrainian Studies and that arose from the Harvard Ukrainian Research Institute’s Millennium Project, an initiative launched in the 1980s to celebrate one thousand years of the Christianization of Kyivan Rus´. The articles cover a wide array of subjects: the ecclesiastical structure of the Christian Church in Rus´ in its earliest period (Andrzej Poppe); the conflict between Orthodoxy and the Uniate Church from 1569 to 1700 (Teresa Chynczewska-Hennel); an account of the Uniate Church and the partitions of Poland (Larry Wolff); the transformation of the Greek Catholic Church under the Austrian Empire (1848–1914) (John-Paul Himka); the Greek Catholic Church in the period between the two World Wars (Andrew Sorokowski); a rethinking of the relationship of Church and society in Galician Ukraine from 1914 to 1944 (Bohdan Budurowycz); and the Russian Orthodox Church in Ukraine during the interwar period (Bohdan Bociurkiw). The book concludes with a bio-bibliography of Bohdan Bociurkiw, a scholar who devoted his career to the study of Ukrainian Church history (Andrii Krawchuk). These essays provide new insights and a fresh perspective to the discipline.