Lead-free ceramics with the most promising piezoelectric properties are based on barium titanate, modified sodium potassium niobate, sodium bismuth titanate, etc. The present book presents the results of a systematic investigation of the dielectric, ferroelectric and piezoelectric properties of this type of lead-free solid solution ceramics as obtained by way of powder X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy, UV-visible spectroscopy, dielectric, ferroelectric and piezoelectric measurements. Also determined was the electron density distribution of five series of lead-free barium titanate piezoelectric ceramics using experimental X-ray diffraction data.