The International Colour Vision Society awarded the 2005 Verriest Medal to John D. Mollon, Professor of Visual Neuroscience at the University of Cambridge, UK. This award is bestowed by the Society to honor long-term contributions to the field of color vision. If the field of color vision were itself a rainbow, then Professor Mollon's contributions cover nearly its full spectrum, including the isolation and elucidation of basic chromatic coding mechanisms and the constraints that they impose on human (and more generally primate) visual performance, the genetic basis of spectral coding mechanisms, the ecological influences on and evolutionary origins of chromatic discrimination. He has been instrumental in the design of several new color vision tests and has extensively exploited abnormal models, both congenital and acquired, to further our understanding of normal mechanisms. He is especially appreciated for his keen and profound sense of the history of science, in particular with respect to the field of color vision. He has been a member of the society for over 25 years and is currently serving on its board of directors. He organized the 2001 ICVS meeting in Cambridge, celebrating the bicentennial of Thomas Young's lecture on color vision.