This dissertation takes the conventional wisdom that Sima Guang's Zizhi tongjian (Comprehensive mirror to aid in government ) was the most important and consequential achievement of eleventh-century Song historiography as the point of departure. A re-examination of the compiling history of the Comprehensive Mirror, however, reveals the intriguingly antithetical relationship Sima Guang held against the official historiography in general and the historical encyclopedia Cefu yuangui in particular. Chapter one proposes to view the official historiography as a mode of historiographical operation in the sense that it had its own place, procedure and product in the Song institutional and cultural context. Chapter two explores the historiographical significance of the Cefu yuangui as a continuing and creative development in the convention of official historiographical operation. The Cefu rewrote both the practically oriented leishu and the received Standard Histories into a taxonomical comprehensive history of lidai junchen shiji. Chapter three turns to the two "New" Histories by Ouyang Xiu. Both were rewritings based on the existing Standard Histories, and yet the stark contrast between one being consistently official and the other being intentionally kept non-official indicated Ouyang's ambivalent role of being both an insider and outsider in relation to the contemporary official historiographical operation. As a matter of interpretation, his "New" Histories were actually old to the extent that both went beyond the later examples of Standard Histories and reached back to the generic quintet of the great Han dynasty historian Sima Qian's Shiji. Chapter four excavates a hitherto rarely studied historical text Gu shi, whose intensive inter-textual relationship with the Shiji and other works by its author Su Che conspicuously embodies the ambiguities of the practice of "re(-)writing" in Song historiographical discourse. It is such a special kind of rewriting that I call it "over-writing." In the Conclusion I have come around to revisit Sima Guang's Comprehensive Mirror in light of the historiographical constellations construed by the preceding chapters. In terms of its (1) resistance to be conditioned by the place (and the culture associated with it) of Guange, (2) development of un-official procedures of efficient teamwork, and (3) textual product in the neither-categorical-nor-biographical format of critical chronology, the Comprehensive Mirror has presented itself as one of its own mode of historiographical operation in the eleventh-century Song China.