It is difficult to summarize any discussion of a subject when its vitality and growth increases and changes almost daily. It has been clearly demonstrated that the immune response is important in all organ systems of the body. Although we have learned a great deal about cellular recognition and the regulatory aspects of immunity, we are literally only scratching the surface of its complexity and applicability. A totally comprehensive review of the immune response is impossible in this short space. We do hope, however, that we have set the stage for the following in-depth reviews of the immunologic disorders in adults.