This book deals with experimental results of the physical characterization of several important, dielectric materials of great current interest. The experimental tools used for the analysis of these materials include X-ray diffraction, dielectric measurements, magnetic measurements using a vibrating sample magnetometer, optical measurements using a UV-Visible spectrometer etc. The materials studied and reported in this book are as follows; the impedance analysis of nanocrystalline NiO prepared using the combustion method; PL (photoluminescence, IR (Infra-red, Raman, and X-ray characterization of GaO powders prepared using the chemical method; X-ray, SEM (Scanning Electron Microscopy), VSM (Vibrating Sample Magnetometer), UV-Vis (UltraViolet-Visible) characterization of the multiferroic material Ga2-xFexO3 prepared using the SSR (Solid State Reaction) method; XRD and optical studies on sol-gel prepared samarium and manganese substituted calcium hydroxyapatite; defect studies and positron annihilation studies on ZnO nano particles prepared using the sol-gel and combustion methods; Bonding in La0.9Zn0.1FeO3 multiferroic material prepared using the chemical method; effect of temperature on the magnetic phase transition in Co0.5Zn0.5Fe2O4 prepared using the mechanical alloying method; effect of sintering temperature on the micro structure and optical properties of ZnO ceramics.