Primary sources in Theatre include: the play itself, a performance, a recording of a performance, prompt books, wardrobe notes, programs, publicity material, annual reports, show reports, photographs, architectural plans. images, advertisements, reviews, costumes, and documentation of stage performance.
Secondary sources comment or critique primary sources AFTER the event. These include: articles, reviews, books and the like.
Tertiary sources combine or digest both primary and secondary sources to provide background on a topic. Examples include: encyclopedias and dictionaries.
The Library has many resources available to find primary sources. You'll find most of them here: