Optical Burst Switching (OBS) is a promising switching architecture to support huge bandwidth demand in optical backbone networks that useWavelength Division Multiplexing (WDM) technology. Due to its special features which combine the merits of optical circuit switching and packet switching, it can support high-speed transmission with fine bandwidth granularity using off-the-shelf technologies. OBS has attracted a lot of attention from researchers in the optical networking community. This book is devoted to a comprehensive discussion of the issues related to supporting quality of service (QoS) in OBS networks. Some of these issues include various mechanisms for providing QoS support to multiple traffic classes including absolute as well as relative differentiation frameworks, edge-to-edge QoS provisioning and other non-mainstream variations of mechanisms that have been reported in recent literature. It is hoped that this work will provide individuals interested in QoS provisioning in OBS networks with a comprehensive overview of current research and a view of possible directions for future research.