依我國傳統學說見解，給付不能之概念乃債務不履行類型化之起點。我國民法債編主要繼受德國一九○○年民法，然其債務不履行之體系，是否果真如傳統見解所言，以給付不能及給付遲延為兩大基本態樣， 為本文所提出之疑問。本文將從學說理論史（Dogmengeschichte）之角度，探討「給付不能」之概念在十九世紀Pandekten法學及德國民法立法時所扮演之角色，冀能由此重新檢視我國債務不履行體系，並建立起銜接我國契約責任法與國際契約法之橋梁。另一方面，德國債法修正之初主張效法國際契約法文件，消除一切給付障礙態樣之區分，然德國二○○二年債法現代化後之給付障礙法制，是否果真脫離類型區分之羈絆，亦為本文之觀察重點。 The concept of impossibility of performance has traditionally been considered as the starting point of the categorization of nonperformance of obligation in Taiwan. Since the Obligation Law of Taiwan is transplanted from the German Civil Code (BGB) of 1900, this article attempts to analyze whether or not the impossibility of performance and the delay of performance are the basic types in our non-performance of obligation system-as it is traditionally regarded. This article discusses the role of the concept of impossibility of performance it has played within the Pandekten legal theory in 19th century and also at the beginning of the German Civil Code (BGB) from the history of dogmas point of view. This Article aims to review the impossibility of performance system in Taiwan and to connect our contract liability law with international contract laws. On the other hand, the draft of the Modernization of the Law of Obligation Act in Germany tended to follow the international contract documents and to eliminate the categorizations of non-performance of obligation. This article examines whether the German Act of Modernization of the Law of Obligation of 2002 is unfettered from the categorization of nonperformance of obligation.