Asthma is a long-term inflammatory disease associated with the airways of the lungs. It involves reversible airflow obstruction and bronchospasm. Some of the common symptoms of asthma include chest tightness, wheezing, coughing and shortness of breath. In some cases, sputum is also produced from the lungs while coughing. These symptoms usually become worse in the early morning and at night, during or after exercise, or on exposure to cold air. Smoking during or after pregnancy, air pollution, exposure to indoor volatile organic compounds, exposure to indoor allergens and bacteria like C. pneumoniae and M. pneumoniae are some of the common causes of asthma. Spirometry is the most common test used for its diagnosis. Atopic and non-atopic asthma are the two broad classifications of asthma. If the symptoms are precipitated by allergens it is categorized as atopic asthma; if not, it is called non-atopic asthma. This book unfolds the causes and mechanisms of asthma which will be crucial for the progress of research in this field. It consists of contributions made by international experts. Those in search of information to further their knowledge will be greatly assisted by this book.