This document provides an introduction to energy, including definitions of energy and power. It discusses different types of energy like potential and kinetic energy. It also covers various forms of energy such as mechanical, electrical, nuclear, electromagnetic, chemical, and thermal energy. Additionally, it examines energy sources, classification of energy sources, energy storage, energy transformation, and world energy production and consumption. Key topics covered include fossil fuels, hydropower, solar, wind, tidal, geothermal, and nuclear energy. Diagrams are included to illustrate various energy concepts.