Cover legend: The Drosophila mushroom body is involved in learning and memory. Here, the mushroom body's intrinsic neurons are labeled by GFP, expressed under the control of the OK107-Gal4 driver. The colors represent depth. The red Kenyon cell bodies form the mushroom's “cap,” with the yellow stalk composed of tightly bundled Kenyon cell axons. The axons fan out at the base of the stalk, where they form synaptic connections with down-stream cells. For more information, see Campbell et al. (pages 10568–10581).