Cover photograph (Copyright © 2006, American Society for Microbiology. All Rights Reserved.): Depiction of hemidesmosome protein complexes (for which the integrin α6β4 is essential for their assembly) at the plasma membrane of keratinocytes bound to the extracellular basement membrane and intracellular intermediate filaments. The photograph is from an oil-on-canvas painting by Kevin Wilhelmsen. (See related article on page 2877.)