Cover photograph (Copyright © 2006, American Society for Microbiology. All Rights Reserved.): False-color low-temperature scanning electron microscope (LTSEM) image of a Streptococcus pneumoniae strain R6 biofilm formed on a glass surface. The use of LTSEM allows for a three-dimensional view of the cells interconnected by small and thin filaments that link the cells to each other and/or bind the cells to the intercellular matrix. As ice crystals grow during cryofixation, they sweep the solutes from the medium into a eutectic boundary formed between neighboring ice crystals. That boundary corresponds to the scaffold-like material (magnification, x6,800). (See related article on page 7785.)