This book discussed about very interesting immunological disorder which affects millions of people in the worlds at different age groups and in different seasons of the year. The etiology of that immunological disorder vary from person to another it may be induced by chemical, drug, infection and even by food. Up to date there is no efficient therapeutic method that cure it completely. It comes even after treatment when the patient exposed to the cause. This immunological disorder is called allergy, which is a reaction by your immune system to something that does not bother most other people. People who have allergies often are sensitive to more than one thing.