Wireless multi hop networks represent a fundamental step in the evolution of wireless communications. These networks are self-expanding, such that their connectivity is only due to existence of the nodes. Such networks can be expanded or decreased simply by adding or removing a node. As a result, these networks constitute a promising solution to expand the network easily as they allow flexibility and rapid deployment at low cost. Many new applications of such networks have recently emerged including Community wireless networks, Last-mile access, Instant surveillance systems, Smart home applications, Local high-speed P2P networking and Connectivity to rural/remote sites. Yet, there are still many open issues in designing an efficient wireless multi-hop networks that need to be solved. This book focuses mostly on some main challenges and heuristics in providing efficient routing in relaying information in such networks.