It depends on which library the book is in. Most University of Toronto libraries have a separate reference section where they keep dictionaries, encyclopedias, and other reference books. Ask for directions at the front desk of the library you're visiting.
If the item you need is not in this location, please go to the call number location in the general collection (called 'the stacks') where older editions of each item may be found.
If you still can't find the book you need, please visit the front desk or email firstname.lastname@example.org.