The following databases are the most promising when it comes to doing research on particular works, genres, or historical periods.
These are reference books they may offer basic theatre history information, especially biographical information or theatrical movements.
To locate items in the catalog that focus on particular theatrical movements, use the name of the movement (ex: absurdism) and search it with theatre or "performance studies".
Most of your books are going to be located on the Basement Level in the P section, particularly the PN section.
Great searches are--
playwright's name AND biography
a particular movement (futurism) or location (i.e. new york)
theatrical technique (lighting, staging, acting)