Co-authored by the discoverer of the piezotronic effect, this book is a fundamental and comprehensive survey of piezotronics and piezo-phototronics. Piezotronics is a term broadly applied to devices fabricated using the piezopotential as a "gate" voltage to tune/control charge carrier transport at a contact or junction. The piezo-phototronic effect describes the use of the piezopotential to control the carrier generation, transport, separation, and/or recombination for improving the performance of optoelectronic devices. The book first introduces the theory of the piezotronic effect and its applications in transistors, sensors, and catalysis. Subsequent chapters comprehensively cover the fundamentals of the piezo-phototronic effect and its impacts on photon sensors, solar