Although Barry Malkin is not credited on American prints of this film, he is listed as editor in several reference works and was named in the press handouts for the film at the time of its British opening in the spring of 1972.
James Goldman's play, oddly, has never been produced on the stage in America; nor would Goldman allow the text of the play to be published, although he later did publish the screenplay of this film. The only stage production of They Might Be Giants took place in London in 1961, when it was produced at Stratford East by Joan Littlewood, with Harry H. Corbett playing Justin Playfair. Goldman felt that the play was unsatisfactory and took the opportunity to rework it as a film script when he and director Anthony Harvey had a big success with the 1968 film of his subsequent play The Lion In Winter.
Joanne Woodward once claimed that the experience of making this film had been so gruelling, she had been tempted to give up acting after finishing it. She would not be drawn further about this, but insisted that this had nothing to do with her co-star, George C. Scott, who had "been a gentleman throughout".
Dr. Mildred Watson: You're just like Don Quixote - everything is always something else.
Justin Playfair: He had a point; he just went a bit too far, that's all. He thought that every windmill was a giant. That's insane. But thinking that they might be? All the best minds used to think the world was flat. What if it's not? It might be round and bread-mould might be medicine and if we never looked at things and wondered what they might be, we'd all still be out there in the long grass with the apes.
Justin Playfair: The earth is shining underneath the soot!
Wilbur Peabody: What's wrong with being Sherlock Holmes, I'd like to know? Sometimes, I wish to God I were the Scarlet Pimpernel.
Blevins Playfair: You don't think you can cure him, do you?
Dr. Mildred Watson : Cure a classic? Once a generation. It's a marvellous disease. The victim's faculties grow keener, ultra-sensitive. His intuition verges on the supernatural. He's capable of things that seem like genius.
Justin Playfair: Is this quincunx your design?