This dissertation offers a theological analysis of the theological condemnations of Fr. Sergius Bulgakov (1871-1944) issued by the Moscow Patriarchate and the Russian Church Outside of Russia (Karlovtsy Synod) in 1935. These condemnations of Bulgakov's theological system, known as "sophiology," provoked a boom of theological literature in the years of 1935-1937, which period historians have named the "Sophia Affair." Although Bulgakov was acquitted of all charges of heresy by his own episcopal superiors within his jurisdiction, the controversy over Bulgakov's theology remains live to this day—hence the necessity of a monographical study of the Affair. The study explicates Bulgakov's sophiology by critically examining four distinct loci of controversy implicated in the theological condemnations. These are Bulgakov's theology of 1) Christ, 2) sex, 3) Sophia, 4) heresy. It is concluded that Bulgakov's critics regularly misunderstood the complexity of his theological views and thus inappropriately judged a number of them heretical. Nonetheless, his opponents in the Sophia Affair in some instances accurately assessed problematic aspects of sophiology, and these are also identified and critiqued. This study argues, in sum, that the Sophia Affair represents a major moment in recent Orthodox theology, insofar as the rising Neo-Patristic synthesis defined itself explicitly and implicitly against Bulgakov's sophiology. This controversy was, furthermore, a sort of "Modernist crisis" in miniature for Eastern Orthodoxy in the 20th century. By clarifying the mistaken assessments of Bulgakov's thought that were generated in the Sophia Affair, Bulgakov's sophiology is suggested as a resource valuable for contemporary theological retrieval.