Final report for a research program in theoretical nuclear physics to develop methods and computer programs to perform ab initio calculations for light nuclei ranging from Helium to Oxygen. The method employed is based effective interaction theory within the framework of the shell model. The principal accomplishments were: (1) participation in the validation of ab initio for {sup 4}He; the first study of A = 6 nuclei with the realistic, non-local CD-Bonn potential; (2) a study of ''intruder'' states in {sup 8}Be, (3) the first shell-model calculations implementing three-body clusters in the effective interaction for nuclei with A> 4; (4) the discovery that two-nucleon interactions by themselves are inadequate to describe the structure of the nucleus {sup 10}B, which provides proof that three-nucleon forces affect nuclear structure; (5) first calculations including the Tucson-Melbourne three-nucleon force, which gives better agreement with the experimental spectrum for {sup 10}B and (6) the development of a new shell-model code designed for public release.