Respiratory tract infections are the infectious diseases that affect the respiratory tract, which is a part of the respiratory system and involved in respiration. These infections are classified into two groups - upper respiratory tract infections and lower respiratory tract infections. The upper respiratory tract is the airway above the glottis. It includes respiratory parts such as nose, pharynx, larynx, and sinuses. The infections of the upper respiratory tract include tonsillitis, sinusitis and otitis media and it causes symptoms such as sore throat, nasal congestion, headache and mild fever. The lower respiratory tract includes trachea, bronchioles, bronchial tubes and lungs. Its infections are more complicated than upper respiratory tract infections. Its most common examples include pneumonia and bronchitis. This book contains some path-breaking studies in the advancement of diagnosis, management and prevention of respiratory tract infections. Those in search of information to further their knowledge will be greatly assisted by this book. This book traces the progress of this field and highlights some of its key concepts and applications.