This book discusses fundamental studies involving the history, modelling, simulation, experimental work, and applications on high-entropy materials. Topics include data-driven and machine-learning approaches, additive-manufacturing techniques, computational and analytical methods, such as density functional theory and multifractal analysis, mechanical behavior, high-throughput methods, and irradiation effects. The types of high-entropy materials consist of alloys, oxides, and ceramics. The book then concludes with a discussion on potential future applications of these novel materials.