Chapter 5 of Performing Music Research focuses on three different types of documents, beginning with pre-existing written, audio, and audiovisual documentation. First, the chapter gives examples of pre-existing documents, such as program notes, which can be used in studies as research data in their own right and as stimuli for research. Second, it considers documentation created specifically for research purposes. This includes recordings of music making, which are a rich source of information in music research, and diaries—whether written, audio, or audiovisual. Third, it considers drawings and other forms of visual representation. Throughout, the chapter highlights the possibilities of obtaining insights from documentary data by using newly developed technologies.