Imaging techniques can now be used to interrogate the anatomical connections of the living human brain. Diffusion imaging, a type of magnetic resonance imaging, provides measurements that can be used to infer the routes of fibre pathways. This approach has already supplied novel insights into human brain anatomy and its breakdown in disease. For example, by tracing the connections of different brain regions, and detecting where these connection patterns change, it is possible to define anatomical borders between cortical regions or subcortical nuclei in the living human brain for the first time. Such non-invasive definition of anatomical regions will help inform imaging studies of functional localisation in the brain, and has potential clinical application, for example, in improving neurosurgical targeting. This talk will provide background to diffusion imaging, highlight recent advances, and discuss the scope and limitations of the technique.