This book is intended as a serious and more-or-less comprehensive text for an introductory college orgraduate course in Mobile Ad-hoc Network for engineers, and it has been meticulously studied, with consistent routing in ad-hoc network. Unlike the traditional wired Internet, where dedicated routers controlled by the Internet service providers (ISPs) exist, in ad hoc wireless networks, nodes act both as regular terminals (source or destination) and also as routers for other nodes. In the absence of dedicated routers, providing security becomes a challenging task in these networks. Various other factors which make the task of ensuring secure communication in ad hoc wireless networks difficult include the mobility of nodes, a promiscuous mode of operation, limited processing power, and limited availability of resources such as battery power, bandwidth, and memory. This book show how some of the well-known traditional routing protocols for ad hoc network fail to provide security. Some of the mechanisms proposed for secure routing are also discussed. This book’s content is designed so that any keen reader would be able to get an overview of the recent topics.