Li Yifu — reliable public information about his life, nationality, and dates of birth and death is limited. What can be confirmed is that the library holds one work by him, The Art of Gauging the Heart (Duxinshu). The book is often classified under social psychology and centers on human motives and interpersonal interaction, carrying the flavor of traditional strategic wisdom and worldly tactics. In style, it emphasizes observation and generalization, using concise language to distill methods for reading people and gauging their hearts, and illustrating them with historical examples and everyday situations so that abstract psychological insights become accessible to ordinary readers. As a widely circulated popular work, The Art of Gauging the Heart has had some influence in the reading of worldly wisdom and psychological strategy, and readers often use it to understand motives and tact in social dealings. Because verifiable sources are scarce, the author's identity and the book's background remain open to discussion; this note relies only on the library's information and the work's thematic features, without inferring biographical details.
