This chapter introduces the principles, classifications, and challenges of wireless power transfer (WPT), focusing on inductive power transfer (IPT) for electric vehicle (EV) charging. WPT is generally divided into near-field and far-field types with distinct operating principles and application domains. IPT is emphasized as the most practical solution for high-efficiency, high-power charging over short distances. The chapter reviews the development of IPT-based EV charging systems, references key standards, and summarizes recent research and industrial progress. It further analyzes major challenges of wireless EV charging, including efficiency degradation under variable load and misalignment, sensitivity to capacitance drift, and interoperability across EV platforms with different coil geometries and voltage levels. The chapter concludes by outlining the thesis objectives, which focus on addressing these challenges through advanced impedance tuning, power regulation, and compensation network optimization to enable efficient, reliable, and broadly compatible wireless EV charging.