An account is given of the observational and theoretical properties that characterize young stars of intermediate-mass (2 ≤ M∗ / M⊙ ≤ 10), known as Herbig Ae/Be stars. The mass range of these objects is an interesting one, since it involves the occurrence of complex phenomena associated with the transition from fully convective configurations, typical of T Tauri stars, to radiatively stable objects, as in the case of massive stars. An overview of relevant observations testifying the variety of surface phenomena associated with the Herbig Ae/Be stars is presented. Recent developments in the theory of the formation on intermediate-mass protostars will also be discussed.