While writing a mystery column on 'mysteries that made it to the movies' for our library e-newsletter I came across this one and decided to see how much it was changed from the book by Fearing and how much it differed from its later appearance as 'No Way Out'. This was very well done. Both my husband and I found it suspenseful and enjoyable. It is much closer to the book. The situation plays out in a publishing venue rather than 'No Way Out''s military background. The 'twist' at the end, if you could call it that, is not as dramatic as it is in 'No Way Out'. I think we were surprised to find that 'No Way Out' managed to use about all of the point plots that appeared in The Big Clock. Bottom line - It is both a good mystery and a good movie. Charles Laughton is very good as the publisher. Yes, you can tell it is from the late 40's era but that does not detract in any way.