這本論文是有關約翰．彌爾頓的共和思想研究。研究所用的主要文本是「王室缺位時期」（Interregnum，1649- 1660）彌爾頓為英格蘭共和國辯護的文章、《失樂園》、《力士參孫》、《復樂園》與《基督教要義》。本文將上述彌爾頓的著作視為真實的歷史事件，意圖展現以下五點。第一，1649年以後，彌爾頓的寫作是對英格蘭共和國重要事件的批判性省思，這些事件分別是：創建英格蘭共和國的正當性、海外軍事勝利對英格蘭共和國的影響、克倫威爾接受護國公稱號並解散殘餘議會、司徒亞特王朝復辟的威脅與復辟。第二，在這些著作中，「自由」與「共和國」是核心的概念。第三，王室缺位時期，彌爾頓從1649年傾向「平民主義」（populism）轉變為1660年支持永久議會。對於彌爾頓的共和思想而言，前述的轉變其實是立場一致。第四，本文將三大史詩視為彌爾頓對共和國崩解的省思，分析三大史詩中的「自由」與「共和國」思想。第五，本文將《基督教要義》視為彌爾頓闡述其基督教神學的最重要著作，並分析彌爾頓對「自由」、「共和國」概念的理解立基於彌爾頓對《聖經》的詮釋。 / This thesis is a study about John Milton’s republican thought. It focuses on Milton’s pamphlets which were written to defend the legitimacy of the Commonwealth of England during the Interregnum: Paradise Lost, Paradise Regain, Samson Agonistes and Christian Doctrine. In this thesis, I take these John Milton’s writings as historical events and intend to elaborate five points. First, Milton’s writings were critical reflection on great events of the Commonwealth of England. These events in turn were the building of the Commonwealth of England, the influences of overseas military triumph on Commonwealth of England, the fact that Oliver Cromwell accepted the title of Protectorate and that he dissolved the Rump parliament. Secondly, liberty and commonwealth were the most important values in Milton’s writings. Thirdly, Milton’s writings were consistent with his political faith during the period from 1649 to 1660. The fourth point is that Milton’s three epics were the reflection on the decline and fall of the Commonwealth of England. Finally, Christian Doctrine was Milton’s most important Christian theology. Milton’s conception of liberty and commonwealth were rested on his interpretation of the Bible in Christian Doctrine.