Cover picture: Two-photon excitation fluorescence intensity and generalized polarization (GP) images of LAURDAN-labeled giant unilamellar vesicles (GUVs) (center and bottom panels) and confocal images of DiI-C18- labeled GUVs (top panel) composed of POPC/ceramides lipid mixtures in different ratios (5%, 10%, 16.6%, 23% molar fraction ceramides from left to right). The images have been taken at the top region of the GUV. High GP values, indicated in red, correspond to gel phase; lower GP values are indicated in orange to blue and correspond to fluid phase. The lack in LAURDAN intensity signal in the gel phase in the polar region of the GUVs is due to the photoselection effect. From the GP pictures it can be concluded that Dil partitions into the fluid phase of POPC/ ceramides mixtures. GUV diameter is ∼30 μm. See the article by Fidorra et al. on page 4437.