歷來關於〈報任安書〉的評論，褒讚者固然很多，質疑而持保留態度者亦有之，若從文類觀點考察其見解，對這篇書信的關注層面顯然多有不同，細加究詰，將可發現仍有許多應當探討的問題。本文首先針對歷來的解釋與評價重新加以檢討，以揭示論題，進而緊扣書信內容及表述方式，就其指稱意向與結構特性，分別討論書信的撰作時機、書信收受者的閱讀反應，並參照相關的政治事件，說明司馬遷有其書寫策略之講究，〈報任安書〉不僅存有暗含的意義，亦有其特定的表述目的。企盼藉由此篇書信較為整全的認識，有助於澄清問題，並給予作者更合理的評價。

Some researchers raised questions or doubts about Sima Qian’s “A Letter to Ren An,” though this letter has been commended by different generations of scholars. We, however, found that their perspectives were obviously different regarding the understanding of the genre. Through careful investigation of this letter, readers might be assailed by doubts. Consequently it is necessary to discuss issues related to this letter. Grounded in the content and expression style of the letter, this article begins with a re-examination of the interpretation and evaluation which previous scholars have made. Next the author will explore the timing for writing this letter and the reaction from the receiver in terms of the referred intention and structural features. Such analyses elaborate on Sima Qian’s creative writing strategy that “A Letter to Ren An” embraces implications related to some political events. By providing a comprehensive understanding of this letter, the author seeks to clarify uncertainties about the above issues and thus an appropriate evaluation of Sima.