Cover picture: Model DNA packed inside icosahedral bacteriophage capsids using a molecular dynamics algorithm that pulls the DNA inside the protein capsid (capsids are not shown). ɸ29 dsDNA (four left panels, with 50% of the DNA packed in the top two orthogonal views and 100% of the DNA packed in the bottom two orthogonal views) exhibit inside-outside concentric spooling about the center. Whereas T7 dsDNA (four right panels) also spools inside-outside, the DNA is organized coaxially about an interior core protein (not shown) that protrudes into the core from the tail of the bacteriophage. In both cases, the loss of conformational space upon packing contributes significantly to the overall energy required to pack the genome. See the article by Locker et al. on page 2861.