The book provides an illustration of popular routing protocols for WSN and also some newly proposed approaches for power efficiency as the sensors being backed up with battery die off as soon as their battery exhausts. The text also provides examples, diagrammatic, graphical and tabular representation of the power efficiency of all the discussed routing protocols. Moreover a fault tolerant system targeted for disaster mitigation application is also investigated. This book is for the readers who wish to explore The routing mechanism in the network and its current development. Apart from this the book also covers the disaster mitigation application using WSN which can aid in development of an early alarm system in advent of a disaster and sustainability of the network in such cases, where most of the public communication systems collapse.