Identity is a term much used yet hard to define. Perhaps for this reason, the concept has long been a favourite with philosophers, and for the very same reason has been avoided by brain scientists, – until now. Greenfield reviews the social perspective from finger prints, to faces, to signatures of the many ways we try to identity ourselves, – in vain. The psychiatric perspective however does offer some valuable clues that then lead to an excursion into the physical brain: the neuroscience perspective. But identity cannot just be an objective phenomenon: hence any pertinent brain phenomena have to be seen also from an individual perspective. Armed with the insights gained from these diverse approaches, actual scenarios in the physical brain that would correspond to familiar examples of identity are examined. However, given the physical brain adapts exquisitely to the environment, and the 21st Century environment is changing in unprecedented ways, perspectives are offered for perhaps facing correspondingly unprecedented changes to our identity.