Renata Adler refuted Pauline Kael's claim that "[George C.] Scott has to be dominating or he’s nothing" by citing this movie. Alongside Scott's divorcee surgeon Julie Christie plays the titular socialite kook who is a bit unhinged and tends to drive all the men mad. Her husband Richard Chamberlain (The Last Wave) does a serviceable psycho. Shirley Knight (Sweet Bird of Youth, The Rain People) doesn't want to get divorced. All are lambs in lions' dens. The vacuity of having it all in 1968. They don't make them like this any more.
Roger Ebert: four stars and a thoughtful review. Also an unqualified thumbs up from Renata Adler at the time in the New York Times. Director Richard Lester did a few things with The Beatles.