This issue of Clinics in Chest Medicine, edited by Dr. Serpil Erzurum and Dr. Sumita Khatri, is devoted to several key areas of interest related to understanding Asthma and its treatments. Topics covered in this issue include: Epidemiology of the Asthma Epidemic in the 21st Century; Classification of Asthma; Genetics and Epigenetics of Asthma; Pro-Inflammatory Pathways in the Pathogenesis of Asthma; Dysfunction of Bronchomotor Tone Pathways in Asthmatic Airway Smooth Muscle; Systematic Approach to Asthma of Varying Severity; Comorbidities and Non-allergic Triggers in Asthma Exacerbations and Severity; Microbiome in Mechanisms of Asthma; Diet and Metabolism in the Evolution of Asthma and Obesity; The Exposome of Asthma; Life Cycle of Childhood Asthma; Asthma over the Adult Lifecourse, considering Gender and Hormonal Influences; Asthma and Corticosteroid Responses in Childhood and Adult Asthma; Immunomodulators and Biologics; Bronchial Thermoplasty; Population Health Models for Asthma; and The Future of Asthma Care: Personalized Asthma Treatment.