Cover picture: Two-photon excitation fluorescence intensity spectra of giant unilamellar vesicles (GUVs) formed by DMPC-DSPC (A-C) and DMPC-DSPC/5% gramicidin lipid dispersions (D-F), labeled with N-Rh-DPPE. The images were taken at the top part of the GUVs at temperatures corresponding to the fluid phase (A, D), gel-fluid phase coexistence region (B, C, E), and gel phase (F). The insertion of the polypeptide leads to drastic changes of the lateral membrane organization. The heterogeneity of the membrane and the large scale concentration fluctuations drastically decrease in the fluid-gel two-phase coexistence region of the binary lipid mixture. See the article by Fahsel et al. on p. 334.