Cover photograph (Copyright © 2008, American Society for Microbiology. All Rights Reserved.): Artistic rendering of adenoassociated virus type 2 capsid pentamers showcasing ribbon and surface models highlighting the prominent HI loop on the capsid surface. Based on recent structure-function studies, the HI loop has been shown to be necessary for proper viral protein incorporation into the intact virion and viral DNA encapsidation. The image was further modified in MacPymol and Adobe Photoshop. (Modeling and artwork provided by Nina DiPrimio, Aravind Asokan, Lakshamanan Govindasamy, Mavis Agbandje- McKenna, and R. Jude Samulski.) (See related article on p. 5178.)