The book collections of the central library "E. R. Caianiello" are mostly located on 'open shelves'; they are, therefore, in the immediate availability of the user, who can access them without the mediation of the operators. For this reason, over the years the physical arrangement of the materials has been reorganized according to criteria that correspond to the chosen arrangement system. The general prospectuses of the shelfmarks of the book collections in the humanities and juridical areas are presented below. The current periodicals displayed in the reading room broadly follow, in the thematic division, the schemes adopted in the corresponding areas. Economic area funds are ordered according to the Dewey Decimal Classification.