Short answers, pulled from the story.
Max Knoll and Ernst Ruska generated the first magnified images of mesh grids placed over an anode aperture in 1931. This device used two magnetic lenses to achieve higher magnifications than any optical microscope could manage at that time.
The first commercial electron microscope appeared from Siemens in 1938. Max Knoll died in 1969 and did not receive a share of the 1986 Nobel prize while Reinhold Rüdenberg also died in 1961 without receiving recognition for the invention.
High-resolution transmission electron microscopy can now achieve resolutions below 0.5 angstroms which equals 50 picometers. This capability enables magnifications exceeding 50 million times while determining atomic positions within materials.
A scanning electron microscope produces images by probing specimens with focused electron beams scanned across surfaces in raster patterns. Steep surfaces and edges tend to appear brighter than flat areas because interaction volumes increase at higher angles of incidence creating a three-dimensional appearance similar to reflected light photography.
Materials need stabilization and enhanced contrast before viewing under vacuum conditions because hydrated biological specimens must undergo ultrathin sectioning to reduce thickness below acceptable limits. Radiation damage remains a severe issue affecting both internal structures and sample integrity during observation.