「別史」是史部類例中較晚出現的，在史部的地位亦相當模糊。雖然可以「上不至於正史，下不至於雜史」概括說明，卻不易清楚戒定其範圍。歷來書目設有別史類者，更是屈指可數。《書目答問》與《四庫全書總目》是近代兩部重要的書目，其史部皆有別史一類。本文乃以此二書目為主，比較其別史類所收圖書分類之異同，希望有助於釐清別史之特性。

The utilization of Bie-shi (alternative histories) as a class in traditional historical classification began in Sung dynasty. Bie-shi is usually defined as “a category which is not as formal as Zheng-shi (Official Dynastic Histories), but not as casual as Za-shi (Miscellaneous histories).” Still, the meaning and coverage of Bie-shi is not quite clear and well-established. It was not a common category employed in traditional historical classification schemes either. Shu-mu Da-wen (Answers to Inquiries into Bibliography) and Si-ku Quan-shu Zong-mu (Annotated Catalog of the Si-ku Collection) are two important bibliographies in Qing Dynasty. They both employed Bie-shi as a category to classify related works. This study attempts to compare and analyze the historical works that were classified in Bie-shi category of these two bibliographies. The goal is to provide a clearer picture about the characteristics of Bie-shi.