This book aims to develop a methodology for WSN routing protocols to consider the energy level of sensor nodes through the establishment and routing processes in order to increase the network lifetime and reduce the energy consumption rate of wireless sensor nodes. Firstly, it develops a novel approach to distribute the responsibility of data routing among most of the wireless sensor nodes in Flat and Hierarchical WSNs. Secondly, another new approach to reduce the transmission and the reception powers is developed to balance the power consumption of nodes. Thirdly, a dynamic mechanism is proposed to distribute the role of the cluster-head among some of the nodes in the same cluster in order to distribute the power consumption and increase the WSN lifetime. Fourthly, a new technique is proposed to consider the energy level of the WSN in dividing the network into clusters and choosing the highest energy nodes to be the cluster-heads. Finally, we develop a method for discovering the optimum route based on the energy level of the intermediate sensor nodes. All the aforementioned approaches contribute in increasing the lifetime of the WSN.