On the cover: Top: Taming the Eye of the beast. Melanoma cells were treated and stained with acridine orange to reveal heterogeneity in response. Middle: LC-MRM was performed using HSP90 client proteins as markers of response after treatment. Proteins that increased in expression are shown red and proteins that decreased in expression from treatment are shown green to reveal adaptive resistance mechanisms. Bottom: Information from LC-MRM was interpreted to design more effective combinatorial treatment strategies, which were validated in 3D organotypic culture. For details, see the article by Vito W. Rebecca et al., pages 1844–1854.