This chapter overviews our past and present energy use and describes the reasons for changes in our energy use throughout history. The sources of energy are considered as well as the geographical distribution of energy use. The reasons for differences in energy sources in different regions are discussed. The distinction between primary energy and end user energy are defined and is discussed in detail in terms of the efficiency of energy conversions. Finally, predictions for future energy needs are presented. These describe the possible changes in proportions of future primary energy sources. The particular situation for transportation energy is considered in some detail.