 the ITU and other regional organizations (e.g. organizations of regulators) are involved in activities for QoS regulation in all regions of the world, besides the standardized approaches for QoS provisioning in Internet-based environments which are done by different SDOs, including the ITU for global standardization and harmonization of telecommunications/ICTs, the IETF for Internet technologies from the network layer up to the application layer, the IEEE for Ethernet, WiFi, etc., 3GPP for broadband mobile networks (2G-5G and beyond), and others. The introduction to this book, given with Chapter 1, aimed to provide information regarding the convergence of the telecom and Internet worlds which is being realized in the first two decades of the twenty-first century, and which is expected to continue toward an all-IP world. However, the traditional telecom world is based on strict end-to-end QoS provisioning, such as QoS in telephone networks for voice services (including fixed PSTN as well as PLMN such as GSM), broadcast networks for TV, and leased lines for business users. Meanwhile, the Internet was developed from the beginning for the best-effort services (i.e. each IP network does its best effort to transfer the IP packets through it) and it is network neutral by nature (e.g. no differentiation of IP packets by ISPs regarding the source or destination address, application, or type of content carried by the packets). The Internet and Internet technologies won the packet-switching technology battle in the 1990s (e.g. with ATM, as Internet major com- petitor from the European side - the European Telecommunications Standards Insti- tute). So, from the end of the 1990s, and especially from the beginning of this century, it was recognized by all SDOs that the telecommunications (i.e. ICT) world and the native Internet world would converge toward the Internet technologies in both main aspects, networking and services. However, the approaches from both sides have merged, and this included QoS support as the main contri