This book addresses artificial materials including photonic crystals (PC) and metamaterials (MM). A first part is devoted to design concepts: negative permeability and permittivity for negative refraction, periodic structures, transformation optics. The second part concerns PC and MM in stop band regime: from cavities, guides to high impedance surfaces. Abnormal refraction, less than one and negative, in PC and MM are studied in a third part, addressing super-focusing and cloaking. Then, applications for telecommunications, lasers and imaging systems are explored.