Xu Xian, whose courtesy name, native place, and dates of birth and death are all unknown, leaves us with very limited public information. All that is currently known is that one work by this author survives, A Collection of Biographies from Unofficial Histories (Baishi Jizhuan), commonly classified under Eastern philosophy. Judging from the title, baishi (unofficial history) originally referred to popular records and miscellaneous anecdotes distinct from official historiography, while jizhuan suggests compilation and narrative transmission. The book therefore appears to be a notebook-style work that gathers old accounts and adds narration, rather than a formal historical classic. Such texts tend to draw on wide-ranging material, covering people's words and deeds, social observations, and fragments of thought, in a plain and concise style that emphasizes record over elaboration. Since nothing is known about the author's life, the background and sources of the work cannot be precisely identified, and its editorial stance and principles of selection still require close reading of the original text. For today's readers, the value of Baishi Jizhuan lies mainly in preserving scattered anecdotes and fragments of ideas, serving as supplementary material for understanding traditional notebook writing and topics related to Eastern philosophy; Xu Xian himself, for lack of sources, remains only a faint figure revealed through this single work.
