The `Rome de Lisle problem' on the vertex and edge truncations has been formulated and solved for all crystal closed simple forms (two, eight, five and 15 for orthorhombic, trigonal + hexagonal, tetragonal and cubic syngonies, respectively). The collections of simple forms obtained are enumerated and considered as special combinations of simple forms in symmetry classes.
Keywords: Rome de Lisle problem; crystal closed simple forms; crystalline polyhedra; symmetry classes; vertex and edge truncations.