This book presents optics as a unified, consistent, and multi-faceted scientific subject, revealing various phenomena rather than a numbered selection of separate optical effects. It addresses, in simple and instructive ways, numerous issues often confused by students. Topics covered include the Fourier transform in a spatial domain, representation of light polarization on the Poincare sphere, conversion of light polarization upon passing through matter, the concept of the phase and group velocity of light, and partial coherence of the optical field.