Book excerpt: The Antibody Molecule reviews the literature leading to current knowledge of the structure of immunoglobulins. The book begins by outlining some of the basic structural characteristics of immunoglobulins without citing the references on which the information is based. Separate chapters follow covering the chemical nature of the active site of an antibody molecule and mechanisms of interaction with hapten; the general structural features and properties of the various classes of human immunoglobulin; and amino acid sequences of human and mouse L chains and of human and rabbit H chains. Subsequent chapters deal with the evolution of the immunoglobulin classes; special properties of mouse, guinea pig, rabbit, and horse immunoglobulins; idiotypic specificities of immunglobulins; and the genetic control of antibodies. This book is meant for immunologists who have not personally observed the development of this exciting period in the history of immunology. It will also provide useful supplemental reading for the serious student or investigator who wishes to become familiar with the nature of the antibody molecule, its genetic control, and mode of action.