Distinguished for his many contributions to eye and brain research, particularly towards showing that the retina comprises not a single sense organ but several, each with its own class of retinal ganglion cells and distinct patterns of connections with the visual centres in the brain. In addition to his discovery and elucidation of the properties of a major new class of retinal ganglion cells, consisting of the smallest cells with the finest axons, Stone has made outstanding contributions to our understanding of the other ganglion cell classes. His work on coding in the visual pathways has completely redirected the study of the problem to a 'parallel-processing' model of information coding. More recently he has established an international reputation in the field of retinal development.