Topics covered in this issue are: Basic principles of Diffusion Imaging; Diffusion MR Imaging: An Important Tool in the Assessment of Brain Tumors; Diffusion MR imaging of Acute Ischemic Stroke; Diffusion Imaging in Demyelinating Diseases; Diffusion Imaging in Brain Infection; Diffusion Imaging in Brain Trauma; Diffusion Imaging in the Neonate Brain; Diffusion MR Imaging for Monitoring Treatment Response; Assessment of Brain Development; Future Horizons in Diffusion Imaging of the Brain.