Cover picture: Smooth endoplasmic reticulum (purple) of a hippocampal CA1 dendritic segment enters the thin neck of a large dendritic spine (gray) that has a highly irregular postsynaptic surface (red). The SER in the head of the spine (seen in the lower figure where the spine is invisible) is thought to provide synapse-specific regulation of calcium and other molecules. See the article in this issue by Spacek and Harris (pp. 190-203).