Human respiratory system is composed of oropharynx, nose, trachea, larynx, bronchi, bronchioles and lungs. The basic function of the respiratory system is to perform gas exchange between the environment and the bloodstream. There are various conditions that affect the respiratory system, including asthma, infection, aging, allergies, and respiratory diseases, such as chronic obstructive pulmonary disease (COPD) and lung cancer. The treatments for respiratory diseases include medications, lung transplant and interventional bronchoscopy. Some preventive measures such as regular exercise, eating a healthy diet, and quitting smoking play a crucial role in the management of these diseases. This book includes some of the vital pieces of work being conducted across the world, on various topics related to the physiology and therapeutics of respiratory diseases. From theories to research to practical applications, case studies related to all contemporary topics of relevance to this field of study have been included herein. This book will provide comprehensive knowledge to the readers.