Cover legend: Neocortical pyramidal cells (black) receive dense connections from nearby parvalbumin-positive fast-spiking interneurons known as basket cells (green). More distant basket cells are not connected (purple). The extraordinarily dense axonal arborization of a basket cell (green lines) underlies the dense inhibition these cells provide to balance the majority of nearby excitatory neurons in an unspecific manner throughout the mouse neocortex. For more information, see the article by Packer and Yuste in this issue (pages 13260–13271).