Wireless power transfer (WPT) is the transmission of electrical energy without wires using electromagnetic fields. It is also called electromagnetic power transfer. In a WPT system, a transmitter device driven by electric power from a power source generates a time-varying electromagnetic field. This field transfers electricity to a receiver device through space. The receiver device then extracts the power from the electromagnetic field and delivers it to an electrical load. WPT technology can eliminate the use of wires and batteries, and thus increase the mobility, convenience and safety of an electronic device. It is useful in operating electrical equipment when connecting wires is inconvenient, dangerous or not possible. WPT mainly falls into two categories, near-field or non-radiative technique and far field or radiative technique. The ever growing need of advanced technology is the reason that has fueled the research in the field of wireless power transfer in recent times. This book strives to provide a fair idea about this discipline and to help develop a better understanding of the latest advances within this field. It aims to equip students and experts with the advanced topics and upcoming concepts in this area.