This authors will write a book on the "Fundamentals of Optical Communications" that will present a systematic and organized view of contemporary knowledge in the optical communications area and be suitable for a Masters level course.They explore the subject of optical communication modeling and theory, covering all the main elements and adopt a viewpoint more biased toward a quantum theoretic than a semi-classical approach. This implies the use of advanced yet practical tools in order to tackle real engineering problems in a field of real interest.The authors cover the main areas of optical communications: propagation, detection, amplification, absorption and generation, and communication. They examine and describe the mathematical underpinnings of the first three areas and then discuss various communication quality issues.