The next generation wireless networks (NGWN) should be compatible with other communication technologies to offer the best connectivity to the mobile terminal, which can access any IP based services at any time from any network without the knowledge of its user. It requires an intelligent vertical handover decision making algorithm to migrate between technologies that enable seamless mobility, redundant best connection and minimal terminal power consumption. Currently existing decision engines are simple, proprietary, and its handover is only based on the received signal strength which has been proven unintelligent. The proposed decision algorithm in this book gains intelligence by combining fuzzy logic system to handle imprecise data, multiple attribute decision making to handle multiple attributes for decision making, and context aware strategies to reduce unnecessary handover. It also detects new network which offers best connectivity than current network and does authentication, and mobile IP registration before making the handover; thereby reducing the packet loss to ensure high quality of service.