Nanostructures can be in the form of nanoparticles or nanograins, nanowires or nanotubes, and nanoplates or multilayers. These nanostructures may be used individually or embedded in a bulk material. In both cases, they share two common features. First, the small dimensions minimize or even eliminate the presence of defects. Second, nanostructures entail large surface or interface areas. The absence of defects makes nanostructure materials stronger than their bulk counterparts, leading to the eventual realization of ideal strength. The presence of surfaces and interfaces may either reduce or increase the strength. Atomistic simulations can provide insight into the deformation mechanism at the atomic and electronic level, something that is very difficult to obtain from experiments. This article describes generic features of nanostructures and summarizes the five areas presented in the articles in this issue.