I investigate properties of atomic nuclei from the first principles or ab initio, which is a ground-up methodology that describes atomic nuclei from basic interactions of their constituents, protons and neutrons. Ab initio methods have more predictive power compared to phenomenological ones. That is important for understanding of exotic nuclei investigated at rare isotope facilities like ISAC/ARIEL at TRIUMF, for understanding of nuclear reactions important for astrophysics, for understanding of fusion reactions relevant for the future energy generation as well as for the testing of fundamental symmetries in nuclear processes. Together with my collaborators, I developed an ab initio method that provides a unified description of both bound and unbound nuclear states and treats nuclear structure and dynamics on the same footing.