Chapter 3: Selected topics in the theory of telecommunications fibers.

This material is intended as Chapter 3 of the book "Optical Fiber Telecommunications II" edited by S.E. Miller and I.P. Kaminow. The chapter consists of 6 sections with the following titles: 3.1 Pulse Propagation in Single Mode Fibers, 3.2 Dispersion Shifted Fibers, 3.3 Polarization Maintaining Fibers, 3.4 Solitons, 3.5 Detrimental Nonlinear Effects, 3.6 Discussion of the LP11 Mode Cutoff.