The cast is first-rate. Julie Harris' Eleanor Lance is the dark heart of the movie. A shut-in forced to care for her ailing mother for years, she has now been released by her mother's death and her own realization that she herself has never truly lived. A poltergeist incident when she was a girl causes Dr. John Markway to invite her to help him investigate Hill House, the malign structure where doors refuse to stay open and "whatever walks there, walks alone." Along with the apparently psychic Theodora and house-owner Luke, Eleanor will investigate the bizarre properties of Hill House. Is there a rational explanation?
Stephen King's The Shining riffs on The Haunting of Hill House, especially in its combination of a deteriorating personality and a malign environment that encourages that deterioration. The movie and the novel have influenced many other works over the years. The movie on its own (movie qua movie?) remains a gem, a sad and horrifying gem that remains as mysterious about the source of its hauntings at the conclusion as it was at the beginning. Maybe moreso. Is Hill House haunted by ghosts or is it itself some sort of malign and inhuman distortion in reality? Answer this yourself. Highly recommended.