Energy deposition is the fundamental physical process by which energetic particles or electromagnetic radiation transfer their energy to a material medium. It constitutes a core research concept investigating the mechanisms, spatial distribution, and temporal dynamics of this energy transfer, leading to phenomena such as ionization, excitation, and thermalization within the absorbing material. This concept is critical across numerous disciplines, including nuclear physics, radiation physics, astrophysics, and materials science, for understanding and predicting the effects of energy absorption, designing energy conversion systems, and assessing radiation interactions.