The thesis examines certain realistic electrode-dielectric configurations and establishes assessment procedures for relative permittivity from capacitance. The parallel electrode geometry having bounded dielectric media in contact with the electrodes of finite thickness is studied numerically over the aspect ratio (electrode separation/electrode dimension) in the range for relative permittivities in the range. Studies on electrode charge re-distribution in the presence of the dielectric suggests a scaling relation that allows relative permittivity to be obtained from a single capacitance measurement. Additional studies with different electrode shapes extend the validity of the scaling relation indicating a universal feature. Experiments have been carried out to validate the numerical findings. Numerical studies on relative permittivity assessment have been carried out for dielectric media extending well beyond the lateral dimension of the electrodes. Procedures for obtaining the relative permittivity of extended dielectric media are established and validated through experiments. Next, assessment procedures for relative permittivity of dielectrics not in contact with electrodes are studied, numerically, for parallel and co-planar electrode geometries. A capacitance mapping system is set up and scanning of extended dielectric media, defect-free and defective, is carried out to demonstrate numerically assisted quantitative assessment of changes in relative permittivity. In the scan mode, co-planar electrode geometry is shown to lead to better spatial resolution of dielectric inhomogneities than parallel electrode geometry. A comparison with air-coupled ultrasonic scan on an extended delaminated composite sample demonstrates that capacitance mapping can either effectively compliment other imaging techniques or can provide an independent quantitative assessment of the medium. Simulation-assisted approach combined with analytical solutions is shown to permit relative permittivity assessment over a wide range of realistic scenarios.