The are multiple concepts of justice, several of which are introduced in this chapter. The need for justice in addressing the great challenges of the world is greater than ever. Whereas technology was once seen as a great social equalizer, it has become clear that technology is more than capable of being used to perpetuate social inequalities, especially poverty. The haves of the world continue to accumulate more, while the have-nots continue to remain behind. Energy use is probably the most direct measure of a country’s development level. It is also the sector most under scrutiny for creating climate change. So, a tension is growing between the need for greater energy capacity in the developing world while there is a corresponding push to reduce energy use and create and develop cleaner sources of energy world-wide.