This essay describes the use of microscopes and microscopic techniques in the examination and identification of samples taken from works of art and museum objects: transmitted light microscopes, metallurgical microscopes, dark field, untra-violet, phase contrast, polarized light, interference and electron microscopy. Staining can enhance otherwise invisible features when using transmitted light. Chemical identification is based on reactions between chemicals viewed through the microscope; crystal shape, color change of paint, corrosion of metals, and blooms. Pigment analysis involves conversion to a soluble salt which then reacts with a specific re-agent. Color or crystal shape identify the element. Pigment characteristics, refractive index, optical properties ( birefringence, pleochroism ) can lead to identification. Forgeries of paintings can sometimes be detected microscopically by examination of cross-sections, wood analysis ( if panel ). Forgery of metal artifacts can be determined by examination of photomicrographs of microstructure. The microscope is an essential tool of both the conservator and conservation scientist.