Leighton Trent’s review published on Letterboxd :
This is one of the 70's best exercises in genre filmmaking. The attention to detail within the color schemes, the production design, the musical score, the wonderful cinematography, even the sound all add up to what is a great thriller by John Schlesinger. It is hard to believe Hoffman is a grad student here considering his apparent age, but what takes place around him doesn't let us dwell on that. The film is paced strategically. I was continually intrigued by the steps it was taking, allowing twists and info to casually fall into place as the story moves along. It keeps you on the edge of your seat and is quite effective in its intensity within most of its scenes. The acting from Keller, Devane, Scheider, Olivier and Hoffman are all convincing and help the film achieve its goal. The aged Laurence Olivier is truly terrific as the villain. He is not overused and we're allowed to truly fear him and his dental tools because of this. The ending, as related to the rest of the film, felt overly dramatic, harsh, even abrupt in comparison to the rest of the film - out of place, really. What I know of the novel's ending I maybe could've seen working in the film, but this ending just does not fit the characters and feels out of sorts tonally with the way the rest of the film has carried itself.