This paper presents an early Ming companion on Chinese calligraphy, the Comprehensive Explanations on Calligraphy (Fashu tongshi 法書通釋) as well as the life of its author Zhang Shen 張紳 (fl. half of the fourteenth century). By analysing the content and the quotations included therein, the present article traces the history and outlines the structure of Zhang’s compendium, while providing also a preliminary translation of the introductory sections of the ten chapters which constitute the entire work. Also, at the same time, through the analysis of biographical materials about the author, Zhang’s life, his official career, personality, and literary works are elucidated. It is concluded that Zhang Shen, an expert classicist as well as a Confucian scholar, whose purpose in his Explanations is to expose and clarify a series of fundamental questions related to the study and practice of calligraphy, which are pertinent to the analysis and interpretation of classical treatises of calligraphy.