This book covers all aspects relating to the structural and electrical properties of HfO2 and its implementation into semiconductor devices. Fundamentals of ferroelectric and piezoelectric properties, HfO2 processes, and the impact of dopants on ferroelectric properties are extensively discussed, along with phase transition, switching kinetics, epitaxial growth, thickness scaling, and more. Additional chapters consider the modeling of ferroelectric phase transformation, structural characterization, and the differences and similarities between HfO2 and standard ferroelectric materials. Finally, HfO2-based devices are summarized.