Cover photograph (Copyright © 2005, American Society for Microbiology. All Rights Reserved.): Hydroxychloroquine causes extensive cytoplasmic vacuolization. Shown is a mouse embryonic fibroblast treated with hydroxychloroquine and stained with 5-chloromethylfluorescein diacetate (green), Lysotracker Red, and Hoechst 33342 (blue). (See related article on p. 1025.)