Wireless Sensor Networks (WSNs) have gained a lot of importance in the past few years. It has a tremendous application in the area of habitat monitoring, forest firing, medical etc. In most WSN applications the energy source is a battery and energy plays an important role in such applications. Therefore, preserving the energy of each node is an important goal during the development of a routing protocol for WSN. There are different routing protocols for WSN operate at minimum energy dissipation increasing the network lifetime. This book contains four chapters. Chapter 1 covers the general...