Cover picture: Geometric model of a chromatophore vesicle from Rhodobacter sphaeroides based on microscopy images and kinetic data. The dimeric units of the light harvesting complexes 1 (LH1, blue Z-shaped structures) and the reaction centers (red) form an equatorial belt around the vesicle. The smaller LH2 (blue rings) are in direct contact with this LH1 array. The Cytochrome bc1 dimers (light blue) and the F0-F1-ATPase (green-red) then sit together at one of the vesicle poles. The yellow arrows indicate how the protons may enter and leave the vesicle. See the articles by Geyer and Helms on pages 921 and 927.