PROJECT SUMMARY/ABSTRACT The goal of this project is to enable scientific discovery and advances in biomedical research through the development of cutting-edge software tools that provide integrated visualizations and analyses of molecular structures and related biological information. Our tools can be applied to diverse types of biomolecular data, including atomic-resolution coordinates, 3D cryo-EM density maps, and protein and nucleic acid sequences, annotations, and networks. We focus on unmet software needs for basic and applied biomedical research using highly trained and talented staff, with excellent interdisciplinary knowledge and specialized, state-of-the-art expertise in software engineering, computer graphics visualization, and data analysis. Our primary efforts are in the interactive visualization and analysis of structures of molecules, molecular assemblies, and protein sequence-structure relationships. These areas are critical for addressing important and highly relevant biomedical problems such as identifying the molecular bases of disease, identifying targets for drug development, designing drugs, and engineering proteins with new functions. Our software tools enable scientists to understand, analyze, and illustrate to others the important principles of molecular structure, function, and interactions. These tools are widely recognized as works of the highest quality, and are available for free on our website in binary and source-code form. We support and maintain these tools, and provide detailed documentation and tutorials. Our technological developments are disseminated widely via scientific publications, lectures, software distribution, and video animations.