Oral immunization has a fascinating and frequently successful history, yet it has been largely overshadowed by other immunization methods. Various vaccines that lead to the induction of antibodies in respiratory, gastrointestinal, and genitourinary tracts are currently under development, and others are in use for the immunization of animals as well as humans. This volume gives oral immunization the attention it deserves in light of recent methodological and technical advances in antigen delivery systems.