Su Xun was the father of the famous writers Su Shi 蘇軾 (1037-1101) and Su Zhe 蘇轍 (1039-1112). He also wrote the ritual book Taichang yinge li 太常因革禮. His collected writings are called Jiadang ji 嘉璫集.
The term shifa and the custom to bestow posthumous honorific titles is said to have been invented by the Duke of Zhou 周公. Essays on this theme were already written by earlier writers like Liu Xi 劉熙 (c. 160 CE), Shen Yue 沈約 (441-513), He Chen 賀琛 (481-549), Wang Yanwei 王彦威 or Su Mian 蘇冕 (734-805), but it was never systematically explored.
The 4-juan (originally 3) long book lists 168 different titles, with 311 references, of which 17 do not appear in earlier texts. Su Xun's study served as a base for the treatise Shifa lüe 謚法略 in Zheng Qiao's 鄭樵 (1104-1162) alternative history Tongzhi 通志.
The Shifa also includes some taboo words (bizi 僻字) that were, during one single dynasty, prohibited for use because the word was included in the name of a deceased emperor. A complicated matter are the names of the mythological emperors, of which it is not known if these are personal names or posthumous titles.