The primary objective of developing improved techniques for calculating the electronic structure of clusters on the basis of density functional theory was accomplished. The methods are the most accurate presently available. The most important topic which is not yet treated satisfactorily in our approach or in any of the competing methods is that of embedding the cluster, i.e., treating its environment properly. New results were obtained for several interesting systems. Keywords Transition metal atoms, Atomic clusters, Electronic structure, Transition elements, Density functional theory, Iron clusters, Nickel clusters.