The Comparative Mammalian Brain Collection web site provides site visitors with images and information from several of the world's largest collections of well-preserved, sectioned and stained brains of mammals, principally those at the University of Wisconsin-Madison and Michigan State University. These collections are currently being consolidated into a central repository at the National Museum of Health and Medicine at the Armed Forces Institute of Pathology in Washington, DC. The collections have been a century in the making and represent the efforts of dozens of skilled scientists. Their colocation at a single facility will represent a national and international center for comparative brain study of the actual specimens. The centralized web site offers many kinds of access to the information contained in the specimens, for use by students and researchers worldwide.