在短短的兩年之內(一九八九至一九九一)，民主化的浪潮席捲東歐地區，其變化之快速與巨大，超乎任何人想像之外。以往的比較共產主義理論和基於 拉美和南歐經驗的民主轉型理論都不能對此提出有效的解釋。面對這種理論的真空，研比較政治和比較共產主義的學者紛紛創立辯說。本文的目的即在於視東歐民主轉型的文獻，並提出修正的功能論以為補充。 本文的焦點在於評論以各種宏條件來解釋東歐民主化的理論。目前學界建構理論的方向大致有四：第一是強調經濟及社會條件造就了政治改革的力量，第二是強調官方意識形態的合法性誤完全喪失，第三是強調統治菁英發動改革，第四是著重於際環境的影響。這四個途徑主要是照造成東歐政治變遷的動力根源來分類的。然而僅僅是了解了這些因素是來自於那一個根源，並不能使我們明白各種因素間的關係究竟是如何。這樣對我們 解釋東歐政治變遷的現南助益並不是很大。本研究因而提出改良的功能論作為研究的基本框架。 改良的功能論將各影響政穩定的因素聯繫在一起，使得各個因素不再是孤立和彼此分離的條件，而是形成一個解釋的整體。這樣做使得我們不必執著於特定的條件，而可以專注於各種不同條件對政權統治機制所造成的淨效果。對於不同的國家(例如發動者的波蘭和追隨者的捷克斯洛伐克)，我們可以強調不同的條件，而不必受某一種動力根源途徑的拘束。事實上，改良的功能論正可作為比較不同政治體系如何倚重不同統治機制以達成政治穩定的理論框架。其廣闊的適用性甚值得進一步的探討。

　　　　　In 1989-1990k the wave of democratization ran through Eastern Europe. The speed and magnitude of such change is beyond the imagination of any log-time observer of that part of the world. However, the theories of comparative communism and democratic transition fail to predict this great process and its outcome. New theories abound. This article reviews this emergent literature, reflects on its strengths and weaknesses, and offers a "modified functional approach." One can find our explanations of political transition in Eastern Europe. The first approach stresses the importance of socio-economic factors in prompting democratization. The second one emphasizes ideological disinter-gration and the resultant loss of regime legitimacy. The third one focuses on the ruling elite in initiating the process of transition. The fourth one stress international elements, such as demonstration effect, arms race, and a reforming hegemon, i.e., Soviet Union under Mikhail Gorbachev. These four approaches basically provide lists of factors that had an impact on the political transformation in Eastern Europe. However, they do not link these listed factors in any meaningful way. This research thus offers a "modified functional approach" as a alternative analytical framework, which anchors the factors of change to a functional theory of political stability and change. In this way, factors are weighed and integrated to provide a meaningful explanation, without being restricted by any of the approaches that fix theoretical attention on a particular source of change.