Pulmonary complications are major causes of morbidity and mortality for patients with compromised airway clearance. Bronchial hygiene therapy referred to any technique utilized to maintain lung sterility by loosening/removing retained secretions for enhancing ventilation and gas exchange. This book focuses on airway clearance techniques and different modalities have been used to assist those who are unable to clear pulmonary secretions effectively, after given a basic background about respiratory system anatomy and physiology. The following information will be useful for respiratory therapist, critical care nurses, and paramedics. I hope that you find this book enjoyable and clinically relevant that because of the simple presentation of ideas and supported figures.