The Miaoscopy Sen/ice and Equipment Core confinues to support each ofthe projects with electron microscopy, confocal microscopy, and digital fluorescence microscopy equipment, services, and support. Users are trained in confocal and fluorescence microscope use, sample preparation, and image analysis. Ultrastructural analysis of cells and fissues is performed by traditional embedded section and embedment- free transmission electron microscopy, and by scanning electron microscopy. High resolution electron microscopic immuno-localization of proteins with colloidal gold coupled second antibodies is performed on embedded and resinless sections. Proteins and nucleic acids are localized in three dimensions by confocal microscopy, or alternatively image stack deconvolution. Live cell microscopy is performed to achieve the biochemical characterization of macromolecular assembly; PRAP measures binding kinefics while FRET can establish complex composifion. The capabilityfor long-term time lapse experiments is offered. The Microscopy Core offers hardware, software, and training for image processing and analsis. RELEVANCE (See instmctions): Imaging technologies, and especially microscopy, are in a period of explosive growtii in sophisticafion, resolution, and power. Increasing, advanced microscopy techniques are essential tools for understanding the changes in cell and tissue organizafion which are central to our emerging understanding of cancer.