This book will cover the recent advances and applications in metamaterials. It begins by presenting the fundamental concepts of metamaterials, including characterization. The book then moves on to discuss microwave metamaterial sensors, metamaterial absorbers in microwave range, metamaterial absorbers in high frequencies, energy harvesting application of metamaterials, seismic metamaterial, artificial intelligence applications in metamaterial antennas, frequency selective surfaces in metamaterials, metasurfaces, and biomedical applications of metamaterials. In all sections, the design procedure of artificial materials and the evaluation of constitutive parameters and related parameters including how they affect results, will be explained. Novel worked examples will be carried out in each chapter.