Cover photograph (Copyright © 2005, American Society for Microbiology. All Rights Reserved.): Field emission scanning electron microscope (FESEM) image of a flagellum-negative mutant of Vibrio cholerae O1 classical biotype strain O395 expressing toxin-coregulated pili (TCP). The use of FESEM allows for a three-dimensional view of the characteristic bundles that are formed by TCP. It can be seen that the fibers in the bundle are physically entwined to form a rope-like or “cable” structure. This property might be the basis for the mechanism by which TCP mediate bacterium-bacterium interactions within a microcolony. The image is visualized at a magnification of ×40,000 and was provided by Louisa Howard of the Dartmouth College Rippel Electron Microscope Facility. (See related article on page 2225.)