Books on theatrical costume can be found in the UBC Library catalogue using subject headings such as:
Some general subjects may also be helpful, i.e.:
Also try subdivisions under classes of people, i.e.:
And try names of individual articles of apparel, i.e.:
Or types of costume, i.e.:
Also check by geographical location, i.e.:
Or names of relevant individuals (note: look for subheadings such as Portraits, or Pictorial Works), i.e.: