Atomic spectroscopy has been applied to a wide range of metals and also to some nonmetals. This chapter discusses the techniques involving the absorption and emission of light by atoms and builds to some extent on the discussions of light, parameters of light, light absorption and light emission. In order to atomize and excite most metal ions and achieve significant sensitivity for quantitative analysis by atomic spectroscopy, however, a hotter flame is desirable. All flames require both a fuel and an oxidant in order to exist. When solutions of metal ions are placed in a flame, the solvent evaporates leaving behind crystals of the formerly dissolved salt. Since all energy transitions that take place in atoms are purely electronic, only individual, discrete, electronic energy transitions are possible. For flame atomic absorption, in which wavelengths of light get absorbed by the atoms, the result is a “line” absorption spectrum rather than a “continuous” absorption spectrum as found for molecules.