This seems to go farther, to cover more ground than the other books for the layman that have come this way. The author covers not only definitions and forms but how far back in history some of them go. The story of allergy as a pathological entity, some of the manifestations that he recounts are almost incredible. His chapters on the nervous and emotional aspects and influences seem a fresh angle. He acknowledges that science, so far, can give the how but not the why.