Real-time observations with electron microscopy

Dynamic transmission electron microscopy allows observation of changes in both the structure and properties of materials at resolutions from the nanometer to the Ångström. Here I review four significant developments in instrumentation and technique that are pushing the boundaries of these experiments, including new optics, new experimental geometries, new ways of imaging solids in liquid and gaseous environments, and developments in ultrafast imaging. These advances will significantly improve our understanding in many areas of materials science, nanoscience, and biological function.