Wireless sensor networks (WSN) are emerging as one of the most important technologies of the 21st century with applications in various areas. Cognitive communications offers a wide potential to overcome major challenges in wireless communications. Cognitive approaches are expected to significantly enhance the efficiency of WSN networks in terms of energy, bandwidth, lifetime, coverage, connectivity, and cost. This book provides a unique and unified framework for cognitive concepts in wireless sensor networks. The text focuses on deployment planning, performance analysis, and hardware implementation