Since the discovery of the lasers in 1960 and optical fibers in 1970, optics underwent deep changes which accentuated its multi-field character. This work covers essential concepts of comprehension and reports the great progress of current knowledge in optics. The method of presentation is inspired by Richard Feynman, with an emphasis on "telling" optics, rather than deducing it from fundamental laws. For its excellent teaching style, the book received the Arnulf-Francon Award by the French Optical Society. The concepts are formulated in a way such that the necessary mathematical tools do not hinder comprehension of the phenomena. Global in vision, the book can also be used as a reference. In addition to the traditional aspects of optics, it includes the tools and methods currently used by researchers and engineers as well as explanation and implications of the most recent developments.