Three subjects are covered in this paper. First, a set of criteria are established to explain how epitaxial growth can be achieved for sol-gel processed ferroelectric thin films. These criteria describe the conversion of amorphous films to epitaxial films. Second, we report the microstructures of ion beam sputtered buffer layers, (100) MgO on (100) Si, and epitaxial bottom electrodes, (100) Pt on (100) MgO and (111) Pt on (0001) A12O3, for the integration of ferroelectric films with various types of substrates. Third, microstructures of the multilayered epitaxial films, (001) YBa2Cu307-δ on (100) KNbO3/(100) MgO and (100) KNbO3 on (100) MgO/(100) Si, are characterized. The results indicate that high quality epitaxial multilayered films can be obtained under the proper processing conditions.