A FEW USEFUL DEFINITIONS 

from A Handbook to Literature, Eighth Edition, Harmon and Holman, Eds., 2000:

PROPAGANDA: Material propagated for the purpose of advocating a political or ideological position; also the mechanism for such propaganda. Earlier, in European use, propaganda carried a positive or neutral sense of "distributing information" or "advertising"; since about 1930, however, the connotations have become increasingly negative. [If the PROPAGANDA link fails, click here, then click "Public relations bookshelf."]

PROPAGANDA NOVEL: A novel dealing with a special social, political, economic, or moral issue or problem and possibly advocating a doctrinaire solution. If the propagandistic purpose dominates the work so as to dwarf or eclipse all other elements, such as plot and character, then the novel belongs to the realm of the didactic and probably cannot be understood or appreciated for its own sake as a work of art. It may be good propaganda and bad literature at the same time. William Godwin’s Things as They Are: or The Adventures of Caleb Williams (1794) is an early example. See PROBLEM NOVEL. 

PROBLEM NOVEL: A narrative that derives its chief interest from working out some central problem. The term is sometimes applied to those novels written for a deliberate purpose or thesis, which are better called PROPOGANDA NOVELS. Because human character is the subject matter surest to interest readers and because human kind is constantly confronted by the problems of life and conduct, it follows that the problem novel - when it is thought of as a story with a purpose rather than for a purpose - is fairly common. The REALISTIC NOVEL, centered as it is in social setting, has often employed social issues as the cruxes of its plots. This matter of illustrating a problem by showing people confronted thereby is at the core of the problem novel.

PROBLEM PLAY: Like PROBLEM NOVEL, its analogue in nondramatic fiction, this term is used both in a broad sense to cover all serious drama in which problems of human life are presented as such, for example, Shakespeare's King Lear, and in a more specialized sense to designate the modern "drama of ideas," as exemplified in the plays of Ibsen, Shaw, Galsworthy, and many others. It is most commonly used in the latter sense, and here it means the representation in dramatic form of a general social problem or issue, shown as it is confronted by the protagonist.