While the E.J. Pratt Library has a fairly good selection of art books (call number range is approximately ND49 - ND800 on the ground level), we might not have any books on your particular selected artist.
You may find a reference to a book that is only available at one of the following libraries, the Art Library (Department of Art History) in Sidney Smith Hall, the Robarts Library, or even at the library at the AGO.
You'll see it listed as "Department of Art Library" as an item location in LibrarySearch
Location: Room 6032B in Sidney Smith Hall (100 St. George Street, Toronto, ON M5S 3G3).
Many of their books are for reading on site (cannot be checked out).
Additionally, you may find the Art History Research Guide by their librarian, Margaret English, to be helpful too (some overlap with this guide but also additional information).
NOTE: Limited Hours, Open to the public on Wednesdays from 1:00 pm to 5:00 pm
By appointment on Thursdays and Fridays.