There are at least two major strategies for searching the discovery system (or any library catalog) for books on a film: 1) by Library of Congress Subject Heading, and 2) by Keyword.
What follows is an example of a search 1) by official Library of Congress Subject Heading. Note that the title of the film is followed (in the subject field) by (Motion picture). Note also that a search for the film The seventh seal must conducted in the original Swedish: Sjunde inseglet (Motion picture):
But you can also search for books that (don't consist of but) contain commentary on a film by searching the keyword or Any field somewhat as follows:
Note that this search returns 75 rather than just 5 results, and that, though the item that came to the top above comes to the top also here, this search returns also books that contain only a chapter or subsection on the film, such as, for example, this one: