Research Files This series is comprised of research notes compiled by Max on various topics related to music hall. These notes were used by Max to compile his research and to provide information when writing articles for the various publications he worked with or responding to enquiries from researchers. They contain mainly photocopies of original songs sheets or photographs as well as printed material from the web, copies of printed publications and articles, and correspondence between Max and other music hall researchers. late 19th century - early 21st century