Use the advanced search in the WorldCat Library Catalog to find books by and about a play or playwright.
For instance, to find work by the playwright Tennsseee Williams, try searching by author for "Williams, Tennessee."
To find books about Williams, or for criticism and interpretation of his work, you might try a keyword search using terms such as "Tennessee Williams" and "Criticism and Interpretation."
You might also try a search using the name of a play or playwright and a term such as "production history" or "stage history." You could also search using more conceptual terms such as "gender" or "masculinity."
Once you have found relevant results, take a look at the subject terms that are used to describe them. Use these terms to build further searches.