ICT is playing an increasingly important role in both business and individual's private life. It has increased international interconnectedness and speed up the process of globalization. But on the other side the total energy consumption by the communication and networking devices and the relevant global CO emission is increasing exponentially. ICT has, in many ways, a vital role to play. It accounts for about two percent of global CO emissions. Telecommunications applications can have a direct, tangible impact on lowering greenhouse gas emissions, power consumption, and achieve efficient recycling of equipment waste.This book is the outcome of the special session on Green Communications at 'The 12th International Symposium on Wireless Personal Multimedia Communications' (WPMC) held in September '09 in Sendai, Japan. To the best of the editors' knowledge this is the first book on the Green Information and Communication Technologies (ICT) and can be considered a milestone and a key-tool aimed at driving the industrial, scientific and academic efforts of the international community to guarantee a greener future to the whole planet.