The Heiress, a 1949 film directed by William Wyler, was adapted from the 1947 play The Heiress, by Ruth and Augustus Goetz, which was adapted from the 1881 book Washington Square, by Henry James. Overall there are many similarities between the novel and the film. The most notable difference is the title.
James's Washington Square seems to have somewhat of a dull title. It hints at the setting of the book but nothing about the characters. Catherine's story could have happened in any setting. Although, when Morris makes Catherine think they are to be married, Catherine assumes that she will never have to see Washington Square again. This is ironic because she does have to see Washington Square again and live there for the rest of her life, just like the title stays the same forever.
Wyler's The Heiress title is a much stronger character title. It explains maybe not exactly the name of a person, but that this person will inherit money and that this person is a female. This title seeps a little into the plot of the story. At the denouement of the movie, Catherine (Olivia de Havilland) becomes a stronger person and looks as though she hates Morris (Montgomery Clift). She rejects him with revenge in mind, not as a lady of her stature should reject a man. The Heiress is more of a proper title for the movie because it creates a stronger Catherine, whereas in the book she is weaker and stagnant.
The Heiress is more appropriate for the movie due to the character development of Catherine. Henry James chose his title Washington Square well because of the same setting that Catherine must endure for all of her lifetime. Both are simple, yet efficient for what story both the director and author want to get across to the audience.