E. L. Cooper In Volume 23 we considered, in seven chapters, the basic armamentarium of the invertebrate immune system and its cells, as well as an analysis of antigens, setting the stage for the initiation of an immune response. We studied cell products, natural or induced, as revealed by nonspecific and specific responses following antigenic challenge such as the pro phenol oxidase system, the lytic responses, the Ig superfamily, and the place this family offers invertebrates and insect hemolymph proteins as candidates for membership. At this point, these various topics seemed to converge,...