Human civilization is chronologically ordered based on the most useful and valued material of the times like stone, bronze and iron. Twentieth century could be classified as the century of Silicon. Since the turn of this century, more than the materials, it’s the lower dimensions of materials that has become significant. We are currently living in an age of nanostructures and nanotechnology. Nanotechnology cuts through all disciplines of science, engineering, and technology. The science of materials at the nanoscale, the interactions between atoms and arrangements plays a key role in these technologies. Transmission electron microscopy (TEM) is a technique used for nanoscale structure and chemical investigations. The talk will detail the use of TEM to study the nature of atomic arrangements in nanomaterials and for investigation of the fundamental material properties including electronic and mechanical properties.