We emphasise the role of interacting Neutrons and Protons in large Shell Model Spaces, interacing by effective two-body interactions , in determining nuclear properties, deformations and spectra. Theoretical formalism to study the many-body interacing system will be discussed. Deformed Hartree-Fock theory and Angular Momentum Projection (along with diagonalisation for band mixing will be discussed. Results of theoretical calculations and comparison with available experimental data will be presented. Some theoretical predictions and expectations will be given for future studies. Some of these will be: High Spin phenomena in including heavy nuclei (rare-earths, Hf, Hg etc) Deformed structures and excited rotational bands in closed shall nuclei (82Ge, 84 Se, 56 Ni, 78Ni etc) Future perspectives: Band structures in exotic nuclei Need for gamma-ray spectroscopy of multiquasiparticle excited configurations References: 1. Zashmir Naik and C .R. Praharaj, Phys. Rev. C67,054318 (2003) 2. S.K. Ghorui and C.R. Praharaj, Pramana 82, 659-669 (2014); S.K Ghorui et. al., IJMP E21, 1250070 (2012)