Cooperative communications is a new communication archetype that enables different users or nodes in a wireless network to share their resources and antennas for distributed transmission/reception. This book identifies a common problem of unbalanced energy consumption in multi-hop cooperative network and then analyzes and develops different proposed solutions and finally presents a cross layer framework for energy efficient cooperative communications in multi-hop wireless networks with a goal to provide significant improvements in average symbol/packet error rate, and the throughput with respect to other transmission parameters.