About the Cover: Targeting anticancer agents to appropriate cells is critical for successful clinical outcomes. Duvvuri et al. (p 309 and Point of View p 271) exploit variations in intracellular pH as a mechanism for selectively delivering drugs to transformed cells but not to normal cells. They found that basic Hsp90 inhibitors were more likely to be targeted to cancerous cells (with high cytosolic pH) than to normal cells (with low cytosolic pH). Shown is a human skin fibroblast compartmentalizing the weakly basic anticancer agent daunorubicin (yellow dots; nucleus is oval in center). The original fluorescence micrograph was provided by the Krise laboratory. Cover designed by Terri Dubé.