The contents of casual love letters include: nourishing heart and beauty, meeting acquaintances, garden layout, room decoration, flower cultivation, stone piling, craft making, painting and calligraphy school, cooking, odor brewing, optimistic life, abstinence, health and longevity, etc. It can be said that it is a great achievement in life, which has not been revealed before. It is said that later writers, such as Lin Yutang and Liang Shiqiu, were all inspired by this book.