Blue gold will play a major role in supplying the world’s energy for at least the next 40 years. This chapter opens with an explanation of what natural gas is (its origin, production and its differences with other gases). We then analyse both the reserves and the consumption patterns of this recent energy. In particular, we illustrate the large and surprising development of gas reserves, observing what is occurring in Mozambique and in the East Mediterranean Sea. We demonstrate why this modern fossil fuel is so attractive to the modern market: its relatively minor impact on the environment, its versatility, its abundance and its competitive price. The major drawback of this fuel – its transportation –is analysed and this leads into a presentation of the details of the LNG sector. We conclude with analysing the current gas markets and the consequences of the gas contracts signed in 1970s and 2000s, which are creating serious difficulties in a rapidly opening market. In this chapter, we will analyse only the situation regarding conventional natural gas. Shale gas is so important – even more shale oil – that we will devote a full chapter to them. It will take time before the energy sector will be entirely based on renewable energy sources. In the meantime, we have to rely heavily on gas.