Based on a graduate course taught at Northeastern University, this book providesa rigorous, practical introduction to the field of optics. Beginning with a history of optics, the book introduces Maxwell's equations, the wave equation, and the eikonal equation, which form the mathematical basis of the field of optics. It then leads readers through adiscussion of geometric optics that is essential to most optics projects. The book also lays out the fundamentals of physical optics - polarization, interference, and diffraction - in sufficient depth to enable readers to solve many realistic problems. It continues the discussion of diffraction with some closed-form expressions for the important case of gaussian beams. A chapter on coherence guides readers in understanding the applicability of the results in previous chapters and sets the stage for an exploration of Fourier optics. Addrssing the importance of the measurement and quantification of light in determining the performance limits of optical systems, the book then covers radiometry, photometry, and optical detection. It also introduces nonlinear optics. This comprehensive reference includes downloadable MATLAB code as well as numerous problems, examples, and illustrations.