Cover picture: Freeze-fracture replica immunogold labeling of connexin32 in one of two gap junctions (green) linking the cytoplasms of the two outer layers of myelin in sciatic nerve of a 3-month-old mouse. Orange, Tight junction strands; blue, cytoplasm; lavender, cortical vesicle pits. X 30,000. For details, see the article by Meier et al. in this issue (pages 3186–3198).