The exhaustive research work being carried out in the field of metamaterials has provided promising devices, components, and subsystems that could potentially surpass the limitations of current technology in many fields like electromagnetic, optics, acoustics etc. The immense technological potential of metamaterials has drawn attention of many researchers worldwide working in microwave (MW), millimeter wave (mmW), infrared (IR), optical frequency regimes, and acoustics for developing novel components and subsystems for various applications. The characterization of metamaterials is an essential pre-requisite for its efficient usage in any of the applications. These include electromagnetic (EM) material characterization (in MW, mmW, and THz frequency regimes), optical characterization, and acoustic characterization depending on the type of materials and applications. It is observed that the analytical and field averaging methods based on simulation tools often lead to erroneous results, while retrieving the constitutive parameters of metamaterials. Hence experimental techniques are essentially required for accurate characterization of metamaterials as the reliability of hardware realization of metamaterial based sub-systems/ components depend extensively on the intrinsic properties.  In view of this, different methods and techniques for characterization of metamaterials are discussed in detail in this book, which will benefit researchers, engineers, scientists, students, and academicians working in the fascinating world of metamaterials. This volume from the handbook series covers almost all aspects of metamaterial science and technology, starting from theoretical modeling, fabrication techniques, measurements procedures till hardware realization. The editors have been chosen from the pioneers and leaders in the field of nanoscience, nano-fabrication technologies for metamaterial science and technology.