Cover photograph (Copyright © 2006, American Society for Microbiology. All Rights Reserved.):Three-dimensional reconstruction of the fluorescent signal (red) obtained by immunostaining exponentially growing Escherichia coli cells with antibodies raised against FtsZ (top left), FtsA (top right), ZipA (bottom left), or FtsN (bottom right). Stacks of optical sections of the fluorescence signal were obtained by mechanical displacement of the z axis, deconvoluted with the Huygens Professional package, and used to reconstruct each colored image using Imaris software. Light effects have been added with Photoshop CS. The black and white outlines are projections of phase-contrast images of the corresponding cells. Perspective effects were obtained using Photoshop CS. (See related article on page 19.)