The Allen Institute for Brain Science conducts large-scale neuroscience research to accelerate understanding of the brain's function in health and disease. It generates open-access datasets, atlases, and tools, including the Allen Brain Atlas with gene expression data from human and mouse brains, and connectomics datasets from electron microscopy imaging of neural circuits. The institute targets the global scientific community by providing free resources for researchers studying neural structure, function, and development. Its work spans projects on cell types, circuits, and human brain mapping, with recent efforts in whole-brain imaging and functional connectivity. Funded initially by Paul G. Allen with over $500 million, it now receives grants from NIH, private foundations, and partnerships like the BRAIN Initiative. Based in Seattle, it employs around 200 scientists and collaborates with universities and tech companies on data platforms. Forrest Collman leads efforts in mesoscale connectomics as Assistant Investigator.