Books (also called monographs) typically give a broad, thorough treatment of a subject, usually from a retrospective point of view. In the Ryerson Library,most books related to dance are located in the GV1580 - GV1799 call number range on the 6th floor.
When you find good sources, you can check the subject headings listed in the subject field of the online record for these books. Then do subject searches using those subject headings to locate additional titles.
Print or write down the citation (author, title,etc.) and the location information (call number and floor). Note whether the book is available or out on loan. When you pull the book from the shelf, you can scan the bibliography for additional sources.