Recent attempts at the synthesis of endohedral fullerenes by organic reactions, so-called "molecular surgery" methods, are surveyed. The creation of an opening on the surface of fullerene cages allowed insertion of He, H(2), H(2)O, or CO within the cages. An effective route to "suture" an opening was established to realize a new endohedral fullerene, H(2)@C(60). Further development of this operation as well as the properties and reactions of H(2)@C(60) are summarized. Also the application of the encapsulated H(2) molecule as an NMR probe for the study of aromaticity of ionic fullerenes is described.