The production of a book devoted to Vaccine Protocols has proved to be a complex task; the variety of procedures required to design, develop, pro­ duce, and assess a vaccine is immense and covers aspects of chemistry, bio­ chemistry, molecular biology, and immunology. Many of the previous volumes in the Methods in Molecular Biology series provide the background required for work on vaccines; of particular interest are the volumes on Immunochemi­ cal Protocols, Practical Molecular Virology, Proteins, and Nucleic Acids. In the volume on Vaccine Protocols, we have tried to cover the latest scientific methods for the design, production, and assessment of vaccines against viruses, bacteria, and parasites. Essentially, the volume is comprised of three basic chapter types. First, a number of chapters describe in detail the development and production of vac­ cines by specific techniques, including genetic manipulation of viruses or bac­ teria to produce live attenuated vaccines or inactivated toxins, and the production of synthetic peptides and conjugate vaccines. Second, a similar number of chapters describe more general techniques that can be used for the formulation, delivery, and assessment of immune responses to vaccines.