Symposium II, "Ion Beams─New Applications from Mesoscale to Nanoscale," was held at the 2011 MRS Spring Meeting, April 25-29, in San Francisco, California. This symposium welcomed presentations on ion-beam engineering and characterization of materials properties, structure, topography, and functionality, spanning dimensions from the mesoscale to the nanoscale. While the unique capabilities of ion-beam techniques in the diverse emerging fields of nanoscience and nanotechnology are fast becoming critical for many new applications, the flexibility of ion-beam techniques now enables the...