Cover legend: Confocal images of white matter axons and glial cells labeled with the multi-diolistic technique. Beads of various mixtures of DiO, DiI, and DiD were delivered to the preparation using a gene gun. Images were acquired by Selva Baltan and Jamie Grutzendler and pseudocolored by NancyAnn Oberheim. For more information, see the article by Baltan et al. in this issue (pages 1479–1489).