Book excerpt: In the field of health, information practices and the organization of knowledge constitute a major challenge today. The practices of the medical profession, or of patients, are evolving under the influence of digital technology. At the same time, the way in which medical knowledge is organized, represented and mediated is also evolving. Information Practices and Knowledge in Health addresses the different aspects of the field of specialized medical and health information; it focuses on the informational practices of professionals in the sector, of patients and, more broadly, of citizens with regards to their health. This book also considers the systems that are used for organizing knowledge in this field.