This chapter discusses the fundamentals of metal–atom synthesis and its experimental methods. Metal atoms can be formed by thermally vaporizing metals under vacuum. The enhanced reactivity of metal atoms compared with bulk metals is partly due to the endothermicity of the atoms and partly due to kinetic factors. The desired atom–molecule reaction will compete only if there is a large excess of the organic molecules; atom–molecule ratios of 1:10 to 1:50 are commonly used to obtain acceptable yields of organometallic products based on the metal vapor condensed. Simple alkanes are generally unreactive toward metal atoms at low temperature. All the methods used for evaporating metals for atom synthesis had been developed originally for the deposition of thin metal films. The interaction of metal atoms with monoalkenes has been investigated on both a spectroscopic and preparative scale. Alkynes have not yielded isolable organometallic complexes in their reactions with metal atoms. A number of new metal–dinitrogen complexes of type M(N2)n have been detected in the reaction of metal atoms with N2 under matrix isolation conditions. The catalytic oligomerization of butadiene is found to occur in most transition metal vapor–butadiene reactions. The interaction of metal atoms with cyclopentadiene is characterized by a tendency toward the formation of a stable electronic configuration for the metal. Reactions of cobalt and nickel atoms with toluene and other arenes yield condensates in which the metal is in a very reactive state. When metal atoms condense on a surface, the recombination to form bulk metal will occur at a rate controlled only by diffusion even at 4 K.