Book excerpt: Blood Group Substances: Their Chemistry and Immunochemistry focuses on the characteristics, reactions, sources, and transformations of blood group substances. The book first offers information on human blood group factors and the methods and reagents used in testing for blood group antibodies and antigens. Topics include autoantibody formation and hemolytic anemia, panagglutinable erythrocytes, effects of temperature on hemagglutination, and effects of periodate on blood group substances. The text also ponders on the sources and purification of blood group substances. The publication examines the chemical and immunochemical characterization of blood group substances and immunochemical similarities and differences among blood group substances from various species. The text then takes a look at antibodies to blood group substances and their biological effects, including purification and concentration of blood group antibodies; studies with antibodies labeled with radioactive isotopes; and passage of antibodies through the placenta. The manuscript is a valuable reference for readers interested in blood group substances.