Protecting the world means defending the country, and even ordinary people with low status have the responsibility. From "Rizhilu": "It is the old knowledge that protects the world, and the later knowledge protects its country. Defending the country, its monarch and its ministers, meat eaters seek it; Those who protect the world are ashamed and responsible. "

The Record of the Day is the masterpiece of Gu, a famous scholar and great thinker in the late Ming and early Qing Dynasties, which has a great influence on later generations. This book is a large-scale academic reading notes written over the years, and it is Gu's work of "recalling the past, reading notes and writing a book". It aims at Ming Dow and saving the world, including all the author's academic and political thoughts, and has the connotation of practical use.