The complete works are relatively good, and there is a good investigation on historical city sites and geographical changes. For example, the ancient Red Cliff has different addresses in different dynasties, and due to the contraction of the Yangtze River estuary, ancient Zhenjiang can watch the tide, which can explain why some dynasties can see poems with swimming tides in Zhenjiang, but later they can't watch the tide in Zhenjiang. If you are interested in history or want to do related research, this book is of great help. Otherwise, many historical facts can't explain, for example, why some Yangtze River ferries chosen for war are historical addresses, rather than more suitable addresses. With the continuous development of China's economic strength, the state should vigorously support the research of corresponding basic disciplines, especially to design an electronic version so as to be applied to the future information war.