Ferroelectric physics is a theory on ferroelectric phase transition for explaining various related phenomena, which is different from dielectric physics. Ferroelectric materials are important functional materials for various applications such as NVRAMs, high energy density capacitors, actuators, MEMs, sonar sensors, microphones and scanning electron microscopes (SEM). This book investigates the dielectric, ferroelectric and energy storage properties of barium zirconate-titanate/barium calcium-titanate (BZT-BCT) based ceramic for high energy density capacitors. It also compares the energy storage capabilities of ceramic powders with polymer-ceramic nanocomposites; and discusses dielectric properties of ferroelectricity in composition distributions.