We discuss the {ITALIC ab initio} No-Core Shell Model (NCSM). In this method the effective Hamiltonians are derived microscopically from realistic nucleon--nucleon (NN) potentials, such as the CD-Bonn and the Argonne AV18 NN potentials, as a function of the finite Harmonic Oscillator (HO) basis space. We present converged results, i.e. , up to 50{\mathchar '26\mkern -9muh}{\Omega } and 18{\mathchar '26\mkern -9muh}{\Omega } HO excitations, respectively, for the A=3 and 4 nucleon systems. Our results for these light systems are in agreement with results obtained by other exact methods. We also calculate properties of ⁶Li and ⁶He in model spaces up to 10{\mathchar '26\mkern -9muh}{\Omega } and of ¹²C up to 6{\mathchar '26\mkern -9muh}{\Omega }. Binding energies, rms radii, excitation spectra and electromagnetic properties are discussed. The favorable comparison with available data is a consequence of the underlying NN interaction rather than a phenomenological fit.

PACS numbers: 21.60.--n, 21.60.Cs, 21.30.Fe, 21.45.+v