An essential, up-to-date textbook in understanding the propagation of light in guided optical structures. The author is the founding member of one of today's leading labs in fiber-optic communications science and he bases the contents on first-hand teaching and lab experience, providing a solid and rigorous scientific foundation, while also considering the applied view point required for an engineering curriculum. He omits fundamental equations of electromagnetism to establish rigorous guided mode solutions, concentrating rather on covering all fiber device modeling used in communication -- ranging from basic concepts of linear guided optics, equations and solutions of wave-applied guiding structures, to optical fiber communication devices. Includes solutions to Maxwell's equations, and a wealth of graphs, calculation methods and numerical problems to illustrate the theory. Supplementary material available free to lecturers.