The newly revised AAO-HNSF ebook on Primary Care Otolaryngology, 4th Edition is a free resource designed to expose all practitioners to the fundamentals of otolaryngology-head and neck surgery. Each chapter reviews the basics of common ear, nose, and throat problems—including a new chapter on sleep medicine. Since this handbook is designed to expose all practitioners to the fundamentals of otolaryngology–head and neck surgery, it can facilitate the recognition of potentially serious problems that should be referred to an otolaryngologist, as well as provide guidance on how to manage uncomplicated problems that can be taken care of by a patient’s primary care provider. We believe that medical students and allied health professionals will find this book both practical and informative in helping you develop the skills necessary to be excellent clinicians.