This article provides an overview of the most common micro-analytical technique in the failure analysis laboratory: energy dispersive X-ray spectroscopy (EDS). It discusses the general characteristics, advantages, and disadvantages of some of the X-ray detectors attached to the scanning electron microscope chamber including the lithium-drifted EDS detector, silicon drift detector (SDD), and wavelength dispersive X-ray detector. The article then provides information on qualitative and quantitative X-ray analysis programs followed by a discussion on EDS elemental mapping. The discussion includes a comparison of scanning transmission electron microscope-EDS elemental mapping and mapping with an SDD. A brief section is devoted to the discussion on the artifacts that occur during X-ray mapping.