This chapter gives a general introduction to energy analysis. At the outset, a brief description of the theory of energy analysis and the techniques used are discussed. Following that, the application of the input-output technique of energy analysis to calculate energy intensities for India is presented. Results of this analysis are presented and trends in energy intensities of sectors in India examined for the period from 1983–84 to 1998–99. Finally, an assessment is also carried out of the likely accuracy of the results obtained, by accounting for some of the possible sources of uncertainties.