Aspects of Developmental and Comparative Immunology contains the proceedings of the 1st Congress of Developmental and Comparative Immunology, held from July 27 to August 1, 1980 in Aberdeen, Scotland. The papers explore various aspects of developmental and comparative immunology and cover topics ranging from the major histocompatibility complex (MHC) and membrane immunoglobulins to idiotypes and diversity, comparative ontogeny, and evolution of lymphoid organ function. Comprised of 105 chapters, this volume begins with an overview of how the host immune system utilizes polymorphic MHC antigens as the principal tool for pseudo-self versus true self distinction. The reader is then introduced to the immunology of earthworms, membrane immunoglobulins, idiotypes, and diversity. Subsequent chapters focus on the evolution of lymphoid organs in vertebrates; differentiation clocks in comparative immunology of mammals and birds; immunorecognition in invertebrates such as insects and gastropods; and the phylogeny of leucocytes in vertebrates and invertebrates. The remaining sections deal with stem cells, immune responses of gut-associated lymphoepithelial tissue, and the ontogeny of resistance to infection as well as the ontogeny of killer cells. Finally, the immunology of fish, amphibians, reptiles, chickens, and mammals is examined. This monograph will be of interest to immunobiologists.