The modem microbiologist is often a real specialist who has difficulty under standing and applying many of the techniques beyond those in his or her own immediate field. On the other hand, most benefits to modem microbiology are obtained when a broad spectrum of scientific approaches can be focused on a problem. In early studies, electron microscopy was pivotal in understanding bacterial and viral morphology, and we still feel that we will understand a disease better if we have seen an electron micrograph of the causative agent. Today, because there is an increased awareness of the need to understand the rela tionships between microbial structure and function, the electron microscope is still one of the most important tools microbiologists can use for detailed analysis of microorganisms. Often, however, the aforementioned modem microbiologist still thinks of ultrastructure as involving negative staining or ultrathin sectioning in order to get a look at the shape of a "bug. " Many of the newer ultrastructure techniques, such as gold-labeled antibody localization, freeze-fracture, X-ray microanalysis, enzyme localization, and even scanning electron microscopy, are poorly under stood by, and therefore forbidding to, the average microbiologist. Even many cell biologists admit to having difficulty staying in touch with current develop ments in the fast-moving field of electron microscopy techniques."