Among the mysteries of the mind which are beginning to yield to the enquiries of contemporary neuroscience are memory and the representation of space. Invited by Sector 6, two prominent neuroscientists discuss the latest research into the way in which the brain encodes a sense of place and the neural basis of memory. Dr Tim Bliss is Head of the Neurosciences Group at the National Institute for Medical Research, Mill Hill. John OKeefe is Professor of Cognitive Neuroscience at University College, London.