  The processes of constructing some graphs from others using binary operations
of union with intersection (gluing) are studied. For graph classes closed with
respect to gluing operations the elemental and operational bases are
introduced. The generating bases together with the system of restrictions on
the gluing operation that preserves the characteristic properties of graphs
form constructive descriptions of the closed classes of graphs.
  It is shown that each closed class of graphs has a unique elemental basis and
at least one operational basis. A constructive description of a closed class of
all graphs and all bases precompletion closed sub-classes of it are considered.
For each of them its characteristic properties and a diagram of the inclusion
of sub-classes in super classes is given. Constructive descriptions are
obtained for some classes of graphs with classical properties. In conclusion,
some possible applications of constructive graph theory are discussed.
