The discovery of Ig E and its association with mast cell histamine release provided the initial understanding of the role of mast cells in asthma and acute allergic reactions. However, mast cells are now recognized as tissue-dwelling effector cells that play multiple roles not only in immediate-type allergic reaction but also in innate immunity, inflammation, angiogenesis, and tissue remodeling. Mast cells produce a variety of lipid mediators, chemokines, cytokines, and enzymes that may interact with inflammatory tissues such as asthmatic lungs. This book focuses on the roles of mast cell products in allergic diseases and discusses strategies to regulate mast cell functions without perturbing their physiological roles. It also aims at understanding mast cells at the system level by creating a detailed model of cell regulation which is expected to lead to highly mast cell-specific, i.e. efficient and safe, drug targets. Allergologists, immunologists and pharmacologists interested in developing new drugs for allergies will benefit from these timely reviews.