With the rapid growth of bandwidth demand from network users and the advances in optical technologies, optical networks with multiterabits­ per-second capacity has received significant interest from both researchers and practitioners. Optical networks deployment raises a number of challenging problems that require innovative solutions, including net­ work architectures, scalable and fast network management, resource­ efficient routing and wavelength assignment algorithms, QoS support and scheduling algorithms, and switch and router architectures. In this book, we put together some important developments in this exiting area during last several years. Some of the articles are research papers and some are surveys. All articles were reviewed by two reviewers. The paper, "On Dynamic Wavelength Assignment in WDM Optical Networks," by Alanyali gives an overview of some issues in the analysis and synthesis of dynamic wavelength assignment policies for optical WDM networks and illustrates a new method of analysis. The paper by Ellinas and Bala, "Wavelength Assignment Algorithms for WDM Ring Architectures," presents two optimal wavelength assignment algorithms that assign the minimum number of wavelengths between nodes on WDM rings to achieve full mesh connectivity. In the paper, "Optimal Placement of Wavelength Converters in WDM Networks for Parallel and Distributed Computing Systems," Jia et al.