Book excerpt: From the first appearance of the classic The Spectrum Analysis in 1885 to the present the field of emission spectroscopy has been evolving and changing. Over the last 20 to 30 years in particular there has been an explosion of new ideas and developments. Of late, the aura of glamour has supposedly been transferred to other techniques, but, nevertheless, it is estimated that 75% or more of the analyses done by the metal industry are accomplished by emission spectroscopy. Further, the excellent sensitivity of plasma sources has created a demand for this technique in such divergent areas as direct trace element analyses in polluted waters. Developments in the replication process and advances in the art of pro ducing ruled and holographic gratings as well as improvements in the materials from which these gratings are made have made excellent gratings available at reasonable prices. This availability and the development of plane grating mounts have contributed to the increasing popularity of grating spectrometers as com pared with the large prism spectrograph and concave grating mounts. Other areas of progress include new and improved methods for excitation, the use of controlled atmospheres and the extension of spectrometry into the vacuum region, the widespread application of the techniques for analysis of nonmetals in metals, the increasing use of polychrometers with concave or echelle gratings and improved readout systems for better reading of spectrographic plates and more efficient data handling.