I voted for The Spy Who Came In From The Cold without looking at the results or reading this thread beforehand. Now that I see the results, I think The Maltese Falcon will be an interesting selection. I honestly didn't know that the film was based off a book. I saw the film a long time ago but luckily have forgotten many of the twists and turns.
At least, I think I have. If I start reading it, they may come back to me.
As for The Spy Who Came In From The Cold, it's in third now and I hope it at least ends up in second place so that it will be part of the second-chance month's selections.