Wireless Sensor Networks (WSNs) are an emerging technology attracting significant research and commercial interest. Routing for WSNs should support the communication patterns that arise in a WSN. In traditional wireless ad hoc network routing protocols based on traditional routing approaches are used. Such protocols are a poor fit for WSN environments for a number of reasons because they were designed for an environment where point-to-point traffic patterns are dominant. Stateless routing protocol, based on geometric routing principles have been proposed for WSNs. Such protocols use node locations to provide geometric navigation between a source and destination. This property is quite attractive to WSNs which are both resource limited and dynamic in nature. However, geometric routing protocols suffer a number of performance and security issues that limit their utility as general protocols. This book discusses these problems of wireless geometric protocols, proposes solutions for both routing algorithm and securities.