Use the Catalogue to find a book on your subject with a popular treatment. (Although this is an academic library, we do try to collect as much as we can on Canadian history, including popular works.) Review the points about scholarly and popular works mentioned here.
Just like with a scholarly book, the most useful way to find a popular book is to find the appropriate subject headings. The distinction between scholarly and popular does not refer to the content, but rather to the approach and intention. Subject headings reflect the subject matter only.