This book presents the theory of influenza and its imaging characteristics. The first part introduces readers to the fundamental theory of influenza, including the etiology, epidemiology and pathogenesis of influenza, influenza-related diseases, and imaging technologies. The second part is divided into 5 chapters and includes extensive DR, CT and MRI images on H1N1 influenza, H5N1, H7N9, H5N6 and H10N8 avian influenza. This book is an ideal reference for the clinical diagnosis of various types of influenza infections, which usually cause epidemic outbreaks and even pandemic of influenza, and small scale epidemic of influenza occurs every 2-3 years. Editor Hongjun Li, is a Professor and Director of the Diagnostic Radiology Department in Beijing You An Hospital, Affiliated with Capital Medical University, Beijing, China.