This book systematically introduces the clinical and imaging characteristics of mediastinal diseases, with emphasis on the essential relationship between clinical diseases and imaging, and on imaging diagnosis and differential diagnosis. This book systematically expounds the etiology, clinical and imaging manifestations, diagnosis, differential diagnosis and treatment of diseases, supplemented by a large number of cases to focus on analysis, focus on clinical thinking, and strive to combine theory with practice, so that readers have a systematic and in-depth understanding of diagnosis and treatment and differential diagnosis of related diseases.