Chronic rhinosinusitis (CRS) is one of the most common health care complaints, with the prevalence of 5-12% worldwide. This book aims to present the new findings in mechanism, diagnosis and management of this widespread condition to clinical practitioners. All practical information about CRS is compiled; therefore busy clinicians would not have to perform exhaustive literature studies to diagnose CRS. This book firstly presents the advances in the understanding of epidemiology, genetics, mechanisms, phenotypes, and immunology of this disorder. In the following chapters, details in clinical diagnosis of CRS are summarized, especially clinical characteristics in paediatric CRS. Later chapters introduce medical, surgical, and innovative treatments of CRS, with brief case studies. The role of allergies, asthma, allergic fungal rhinosinusitis, and systemic diseases are also discussed. With the illustrative figures, this book is a comprehensive and quick reference to otolaryngologists, paediatricians, family care physicians, allergists, professional clinical staff, and medical students.