法國飛行員作家安東尼‧聖修伯里在1941年到1943年滯留紐約期間，除了《小王子》外還完成並出版《給人質的信》。他將前一本書提贈予雷翁‧維爾特，而後一本書原意是要給雷翁‧維爾特的一封信，同時作為維爾特之回憶錄《三十三日》的序言。本文首先說明《給人質的信》的發想命題和出版經過，接著參考亞里士多德、西賽羅和昆第良等西方古典修辭學著作，依循布置安排來概述《給人質的信》六個部分的內容與風格，接著採取各種喻說、意念辭格和措詞辭格等來閱讀作者的遣詞用句，分析其論證觀點和駁斥集權主義的方式，並加以對照該書及作者其他著作的內容，以期理解聖修伯里在彼時彼地對於朋友和國家的思念和憂慮，同時具體呈現作家如何透過文學創作祈使美國等盟邦同情和伸援法國，拯救如同人質的四千萬同胞。
During his self-exile in New York, Antoine de Saint-Exupéry not only wrote and published The Little Prince, but also Letter to a Hostage in 1943. While the French aviator and writer dedicated the first book to his Jewish friend, Léon Werth, he also wrote the draft of the later based on a letter originally addressed to Werth. This letter was also intended to become the preface to Werth’s memoir called 33 Days, a chronicle of a-8-million-people exodus during the German invasion in 1940. Werth asked Saint-Exupéry to smuggle the manuscript of 33 Days to New York for him and to get it publish in America. For some unknown reason, 33 Days had not found a publisher until 50 years later. Tormented by his friend’s unsuccessful publishing project, Saint-Exupéry was also worrying about Werth’s safety in occupied France. To turn these unfortunate events into a positive one, he rewrote and expanded the original letter to Werth before publishing it firstly as a wartime booklet. Letter to a Hostage includes Saint-Exupéry’s interpretation of the essence of humanity after experiencing the solitude in Sahara and being captured by the Spanish armed anarchists. In fact, the six parts of the booklet can be read in line with the six parts of a discourse in Rhetorica ad Herennium, for Saint-Exupéry aptly used many rhetoric devices in it. This essay begins by providing background information about 33 Days and Letter to a Hostage, then by using classic rhetoric works by Aristotle, Cicero, Quintilian, etc. as references, it will... followed by the description of ‘the inventio’ in Letter to a Hostage the disposition and style of each part; some brief introduction and topic in each; the maneuvers of various tropes, figures of thought and figures of speech; and the methods of demonstration and refutation, such as examples and enthymemes, used by the author in order to conciliate the French with opposite opinions and to denounce the totalitarianism. Finally, by comparing Letter to a Hostage with some other works of Saint-Exupéry, we wish to understand the writer’s reminisce about Werth and France, while demonstrating how the writer voices his appeal to America for intervention in World War II and his attempt to save the “forty million” hostages through literary writing.