This book presents an in-depth exploration of High Entropy Alloys (HEAs), a new family of materials, characterized by a unique set of properties. It sketches the background of the HEAs from the time they came into existence to the present day as a material of interest in many leading industries. In today’s fast-paced, advancing technologies, HEAs have takencenter stage in presenting optimum solutions to the challenges of modern engineering problems. The book addresses systematically the fundamental principles underlying HEAs, their classifications according to the compositions and constitutions and their exceptional mechanical, thermal and chemical attributes and their manufacturing routes. It further discusses the growing number of engineering applications of HEAs across aerospace, defense, energy and biomedical industries. By tackling the theoretical premises and practical results obtained in the past, the work highlights the dynamic research being conducted on HEAs and their promising future. The book supplies a precise and detailed appreciation of the key role of HEAs to a readership that consists of researchers and students working in the field, as well as industry players alike.