The explosive development of ICT (information and communication technology) industry has emerged as one of the major sources of world energy consumption. In fact ICT industry ranks among the top energy consumers, with 2% to 10% energy consumption in the world, which is expected to get more demanding in the future due to increase in the density of base stations in 4G wireless communication networks. Toward realizing ubiquitous computing environments, wireless technology is enhancing the mobility of ubiquitous devices, but this mobility creates a power management problem. Consequently reducing the energy consumption of wireless networks is considered vital for the future. This book is focused to perform a detailed assessment of various energy optimization techniques being used or proposed to achieve sustainability in the mobile wireless communication networks. Also, a comprehensive study is carried out on the health implications of Mobile Radiations and the sustainable approaches to address the issue.