"Supergravity is a theory of gravity which has supersymmetry, a symmetry between bosons and fermions. Supersymmetry in supergravity is a local symmetry like the gauge symmetry in the standard theory of particle physics. The gauge field of the local supersymmetry is the Rarita-Schwinger field, which represents a particle with spin called a graviton. Supersymmetry also has a local symmetry under the general coordinate transformation, whose gauge field is the gravitational field. An important role of supergravity is in its relation to superstring theory. ... Supergravity provides a low energy effective theory of the massless sector of superstring theory and can be used to study its low energy properties."