On the cover: The NATIONAL TECHNOLOGY CENTERS FOR NETWORKS AND PATHWAYS program was designed to tackle fundamental technological challenges inherent in acquiring quantitative information at the subcellular and biologically relevant timescales necessary for temporal and spatial characterization of complex biochemical pathways and molecular interactions. The figure depicts the circularity of the process of dissecting cells to component parts and reassembling them in abstract forms to arrive at coherent models of macromolecular dynamics. Cover art was provided by The Institute for Systems Biology, Seattle, WA.