Ad hoc networking attracts more and more attention amongst researchers. It includes a variety of topics involving many challenges. In this book, we dealt with security problems and focused on one related to the energy constraint of the nodes forming the network, namely node selfish misbehavior or node non-cooperation. This problem is specific to ad hoc networks and threatens the service availability, which one of the security requirements. A misbehavior router, anxious about its battery shortage, drops packets originated from other nodes, while using them as routers to relay its own packets. A general review of some security problems has provided, with more focus on the selfish misbehavior. The power management that is the main cause of this misbehavior has been tackled, and a power aware-routing protocol has been proposed. This helps increasing the battery life time, but it is far from eliminating this challenging problem. Therefore, a solution that detects and isolates selfish nodes is mandatory for self-organized ad hoc networks. A new solution to monitor, detect, and isolate such nodes has finally been proposed, analyzed, and evaluated.