A new linked cluster expansion for the calculation of ground state observables of complex nuclei with realistic interactions has been developed [1-3]; using the V8 potential [4] the ground state energy, density and momentum distribution of complex nuclei have been calculated and found to be in good agreement with the results of [5], obtained within the Fermi Hyper Netted Chain, and Variational Monte Carlo [6] approaches. Using the same cluster expansion, with wave function and correlations Realistic Calculation of the Effects of Nucleon-Nucleon Correlations in High-Energy Scattering Processes Off Nuclei parameters fixed from the calculation of the ground-state observables, the semi-inclusive reaction of type A(e,ep)X has been calculated taking final state interaction effects into account within a Glauber type calculation as in Ref. [7]; the comparison between the resulting distorted and undistorted momentum distributions provides an estimate of the transparency of the nuclear medium to the propagation of the hit proton. The effect of color transparency has also been considered within the approach of [8,9]; it is shown that at high values of Q^2 finite formation time effects strongly reduce the final state interaction, consistently with the idea of a reduced interaction of the hadron produced inside the nucleus [10]. The total neutron-nucleus cross section at high energies has also been calculated [11] by considering the effects of nucleon-nucleon correlations, which are found to increase the cross section by about 10% in disagreement with the experimental data. The inclusion of inelastic shadowing effects of Refs. [12,13] decreases back the cross section, leading to a good agreement between experimental data and theoretical calculations.