This dissertation is a study of the most important Greek patristic commentary on the Book of Revelation, composed in 611 by Andrew, "Archbishop of Caesarea, Cappadocia. The dissertation consists of two parts: Part 1, Studies on the Apocalypse Commentary of Andrew of Caesarea, and Part 2, Translation of the Apocalypse Commentary of Andrew of Caesarea. Part 1, Studies on the Apocalypse Commentary of Andrew of Caesarea, consists of an analysis of the commentary and an explanation of the Book of Revelation in the history of Eastern Christianity. Chapter 1 is an introduction to the commentary and to the historical context, audience, purpose and motivation for its composition. Chapter 2 discusses the Book of Revelation in the canon of Eastern Christianity through an historical overview of the place of Revelation in the canon of the East from the second century through the present day. The chapter considers which factors accounted for the early and immediate appeal of Revelation, examines the attitudes toward it as revealed in primary sources, and demonstrates that the Apocalypse was consistently recognized as an apostolic document from the second century through the early fourth century. Revelation eventually came under attack due to its association with controversies such as Montanism and chiliasm. Doubts about its authorship were raised to discredit it in order to undermine the controversial movements which relied upon it. It remained in an uncertain canonical status until relatively recently and is now presumed to be part of the New Testament by most Eastern Christians but the question of its status in the canon has never been "officially" resolved. Chapter 3 explains the importance of the commentary from a text-critical perspective and for the purpose of studying the history of the Apocalypse text itself. A large percentage of Apocalypse manuscripts contain the Andréas commentary, which has preserved a text type of its own, and the study of the Andréas text type facilitates the analysis and evaluation of other text types by comparison. This chapter also discusses the dual textual transmission of the Book of Revelation, unique among the books of the New Testament, since manuscripts of Revelation are found both in scriptural collections as well as bound with a variety of spiritual and profane writings. Chapter 4 discusses Andrew's commentary in the context of the trajectory of other ancient Apocalypse commentaries, East and West, and how the interpretative history proceeded along a dual stream of tradition. The first commentators greatly influenced those who followed them, but only those who wrote in the same language. The Latin tradition did not influence Greek interpreters, nor vice-versa, and commonalities between Greek and Latin writers can be traced back to the earliest Fathers and to the perspectives, Scriptures, exegetical techniques and traditions common to both East and West from the first centuries of Christianity. Chapter 5 commences an evaluation of the commentary itself, including Andrew's purpose, motivation and orientation, as well as a discussion of the structure, style and characteristics of the commentary. This chapter also explains Andrew's methodology, techniques and use of sources. Chapter 6 explores Andrew's theology, including his doctrine, view of prophecy, history, eschatology, angelology and salvation. Chapter 7 reviews Andrew's influence on subsequent Eastern commentators, the translation of his commentary into other ancient languages, its impact on the reception of the Book of Revelation into the Eastern canon and the commentary's lasting pre-eminence and importance. Part 2 of the dissertation, Translation of the Apocalypse Commentary of Andrew of Caesarea, is an English translation of the commentary with extensive explanatory footnotes.