Cover legend: Digital reconstructions of neuronal arborizations imaged with optical or confocal microscopy enable quantitative morphometric investigations and computational modeling. The cover illustration is a mosaic of hundreds of cortical cells, rendered as binary trees, available at NeuroMorpho.Org, the internet database described in the Toolbox by Ascoli et al. in this issue. Sharing these files leads to new fundamental discoveries, such as the recent demonstration of dendritic homeostasis: if a part of a neuron is larger than average, another part of the same neuron tends to be smaller. The color gradient illustrates this concept, with corresponding dark/light shades of blue and brown. Image by A. V. Samsonovich and G. A. Ascoli (Krasnow Institute for Advanced Study, George Mason University, Fairfax, VA). For more information, see the article by Ascoli et al. in this issue (pages 9247–9251).