Dr Roger Keynes is an inspiring scholar who has had a major influence on our current thinking on neural patterning during embryonic development. His most important contributions relate to the problem of segmental patterning in both the Central and Peripheral Nervous System. It was he who first recognized that motor and sensory nerves have to develop in line with the neighbouring structures and to demonstrate that it is indeed the latter (the somites) that dictate pathways through which motor and sensory nerves grow, generating a repeated pattern along the body axis. He was also the first to recognize, as early as 1985, that morphological subdivisions of the hindbrain (later called rhombomeres) were not artefactual but could represent real functional units, a concept that has since been proven correct, and "common knowledge" as a result of the collaboration he initiated with Andrew Lumsden shortly afterwards. Since then, his research has concentrated primarily on understanding the molecular nature of the guidance cues in the somite that direct motor and sensory axons, being among the first (1986) to recognize the importance of repulsive (or inhibitory) cues alongside attractive ones. More recently, his research has once again uncovered previously unsuspected influences between the mesoderm and the CNS, revealing that the notochord under the midbrain regulates the growth of the tectum and that the notochord might be intrinsically segmented, despite the widely held belief that it is not. Without exception these contributions were due to his perceptive sense of biologically important questions, to his scholarship and to his choice of collaborators and the enthusiasm he was able to instill on them.