Compendium of Materia Medica has 459 pages. This book is the crystallization of more than 30 years' painstaking efforts of Li Shizhen, a medical scientist in Ming Dynasty. The book has 40 volumes, 52 volumes and more than 200,000 words. It is the representative work of China's Materialism before16th century. This book has great enlightenment and far-reaching influence on the development of materia medica and the research of later generations. The pdf version of Compendium of Materia Medica of the World Digital Library is also 459 pages, and users can get it for free through the platform.