Allergic diseases and asthma constitute a growing health care problem with a marked socioeconomic impact, especially in industrialized countries. This book summarizes what is currently known about the mechanisms underlying these diseases. Obviously, both environmental and genetic factors influence the development of allergic and asthmatic diseases. Several chapters highlight the role of eosinophils, lymphocytes, and T cells, as well as environmental factors in the development of allergy and asthma. Also discussed are the most recent therapeutic strategies including allergen-specific immunotherapy and anti-IgE treatment as well as the function of histamine as a major mediator of acute inflammatory and immediate hypersensitivity reactions. The interdisciplinary character of this book is documented by articles from various fields such as environmental, molecular, and cellular biology, allergy and dermatology. Representing an excellent collection of state-of-the art reviews, this publication is indispensable for all scientists working in allergy and asthma and for clinicians treating allergic and asthmatic patients.