Cover image: The cartoon depicts infrared femtosecond pulses aimed at amide-I modes of polypeptide bundles. Cross-peak regions (arrows) in the 2D infrared spectrum of the transmembrane helix dimer of glycophorin A provide evidence that vibrations are delocalized over both helices. See the Perspective by Hochstrasser on pages 14190–14196. Image courtesy of Robin M. Hochstrasser.