Rosemary's Baby is a tolerably successful commercial movie, which is to say it isn't very good, and a clear disappointment to anyone who has admired—if only in part—Roman Polanski's earlier films. If it does fail as a horror film, however, it is, I think, because Polanski's main interest lies elsewhere: the humor of the film, especially the wit of the ending, makes the film worth considering. To begin with, any reasonably sophisticated person's response to the movie's ending is likely to be: but there are no witches. No effort is made to suspend your disbelief in witches; they are just a "given," a dramatic assumption never made compelling. This problem of belief is especially acute because the action of the film is here and now: the supernatural, the world of witches, is easier to believe in when it is made somehow remote, or removed from the...