Cover photograph (Copyright © 2005, American Society for Microbiology. All Rights Reserved.): The center shows a false-color-coded visualization of the 3D structure of Acidianus bottle-shaped virus (ABV) obtained by electron tomography (approximate size, 230 by 75 nm). Other images, clockwise from top left, show a single, negative-stained ABV virion, digitally imaged by transmission electron microscopy; four ABV virions, attached to each other with the ring of filaments; a partly disrupted virus, displaying parts of its interior structural components; and a tomographic section through the 3D reconstruction of the virion. (See related article on page 9904.)