Sansheng bianfang beilan 三省邊防備覽 is an overview of the defence structures of the three western provinces of Sichuan, Shaanxi, and Hubei. The book of 18 juan length was written by Yan Ruyu 嚴如熤 (1759-1826), courtesy name Bingwen 炳文, style Leyuan 樂園, from Xupu 敘浦, Hunan. Yan was surveillance commissioner (anchashi 按察使) of Shaanxi and also wrote a book on maritime defence, Yangfang beilan 洋防備覽. His collected writings are called Leyuan shiwen ji 樂園詩文集.
The book is the result of a collection of memories written down during more than twenty years of travels in southwest and west China. In a first draft, Yan assembled his notes in the books Sannei fengtu zazhi 三內風土雜志 and Bianjing daolu kao 邊境道路考. He finally decided to submit a refined version of these drafts to responsible officials. This was in 1822.
The book is divided into 11 chapters speaking of geography, traffic (roads and waterways), eminent persons, passes, population, commerce, military affairs, administration, history, and literature. The texts follows a geographical arrangement and is enriched by several maps.
The book was reprinted in 1840 and in 1882. The latter edition, published by the Sanyu Shushi Press 三漁書室, has a length of only 14 juan.