Ceramic materials and single crystals showing ferroelectric behavior are being used in many applications in electronics and optics. A large number of applications of ferroelectric ceramics also exploit properties that are an indirect consequence of ferroelectricity, such as dielectric, piezoelectric, pyroelectric and electro-optic properties. This book introduces the basic principles and characteristics of ferroelectric materials and lists various materials chosen from single crystals, ceramics, polymers and ceramic-polymer composites which show ferroelectric behavior. Many different applications arising from ferroelectricity and related phenomena in ceramics and thin films have been discussed with their processing techniques