The development of new or improved vaccines using biotechnological techniques is especially important for developing countries, where traditional means of vaccine manufacture are frequently not available. This volume explores the four main approaches for developing alternative vaccines: the use of live agents; the use of anti-idiotype antibodies; the introduction of DNA or cDNA coding for a protective antigen of the disease agent into a mammalian cell line, into a lower eukaryote, or into an appropriate bacterium; and the synthesis of oligopeptides corresponding to an epitope or a protective antigen of the disease agent.