- The proposed book provides a thorough understanding of the complexities involved in implementing energy efficient cross layer protocol for WSN.- An extensive, well researched literature survey of the state-of-the-art was conducted to implement an effective Cluster Head selection for Wireless Sensor Network.- The proposed work successfully addressed significant issues related to Energy optimization in WSN through the use of well-established theoretical, analytical and simulate methods.In this book energy efficient protocols in wireless sensor networks are innovated and implemented. It is conclusively demonstrated that the proposed protocols are more energy efficient compared to the protocols discussed in the research literature.