Since 1990, research on nanostructures and nanoparticles has attracted the interest of many researchers. Several methods have been developed to fabricate nano-sized materials. The main concern is to establish method that can be used to produce these materials at low cost, which is attractive for industry. In this book, it was attempted to develop new routes for preparing ZnO and PZT nanostructures, which are the two materials that have attracted the most interest in this decade. Four different preparation techniques have been used to prepare ZnO nanoparticles, i.e., sol-gel synthesis, sol-combustion synthesis, solvothermal synthesis, and sonochemical synthesis. In addition, the sol-gel synthesis process has been used to prepare PZT nanoparticles. The structures of the ZnO and PZT nanoparticles also were investigated theoretically. Different theoretical models, such as Williamson-Hall, Size-Strain Plot, and Kramers-Kronig were applied to analyze the XRD and FTIR data of the the ZnO and PZT nanoparticles. The dielectric properties of the PZT nanoparticles (with and without PVDF matrix) were investigated in the frequency range of 100 Hz to 40 MHz.