The word "book" can mean a number of things. For the purposes of this guide, a book is a printed object, sometimes printed onto one sheet but more often onto multiple pages and bound together. Books that are rare or unique, or that contain the source text being studied, are considered primary sources. Of particular use to performing arts researchers are:
- Play texts, libretti, scores, dance notation, and other kinds of texts that capture the content of a production.
- Biographies of figures in the performing arts.
- Published promptbooks. A subcategory of this are "acting editions," which print the play text along with the stage directions. Samuel French is probably the most well known publisher of acting editions.
- Festival books. These commemorate a large performative event, such as a parade or firework spectacle. For example, many of Lully's performances staged at Versailles are represented in festival books. Some amount of skepticism should be used when interpreting festival books, as they do not always represent the historical occurrence. Instead, they often depict an idealized (or entirely fictionalized) version of the event.
- Instructional Manuals. Harvard holds a number of manuals on theatrical technologies, skills, and business, including makeup, lighting, costume, magic tricks, animal performance, and more.
- Sales catalogs. Harvard also holds a number of sales publications from makeup and costume companies, as well as printers specializing in performance materials like posters and playbills.