The book reviews our current knowledge of piezoelectric materials, including their history, developments, properties, process design, and technical applications in such areas as sensors, actuators, power sources, motors, environmental and biomedical domains. Piezoelectric materials will play a crucial role in the development of sustainable energy systems. Keywords: Piezoelectric Materials, Piezo-crystals, Nanogenerators, Phototronics, Piezoelectric Composites, Biomedical Applications, Energy Harvesting, Piezoelectric Thin Films, Piezoelectric Perovskites, Sensor Applications, Piezoelectric Ceramics, Piezoelectric Semiconductors, Piezoelectric Polymers.