This film had 3 Academy Award nominations and also won several other awards. How I happened to have missed seeing this back when it was released is bit of mystery to me but nevertheless I have now seen it and enjoyed it very much. Samantha Eggar was one of the nominees for best actress and she is perfect for this thriller. IMO, Terrance Stamp who won the best actor award at Cannes should also have been nominated by the academy but was not. The director was William Wyler (also a nominee) and he has left a very fine film even today 46 years later.
There is a long detailed synopsis of the film on the IMDB but I would caution anyone who has not seen the film to postpone reading it since it gives away too much and is a spoiler.
Suffice to say, that I will be watching this one again.