What makes a brilliant script? Is it quotable lines? Is it nuanced dialogue? Or is it just the ability to move the story along and not get in the way? When looking back through the history of screenwriting, there are plenty of iconic films based on previous work; the Writer’s Guild of America voted Casablanca the greatest screenplay of all time, but it’s adapted. So, what is the most important piece of film writing ever written directly for the screen? This list will shift from American to international, conventional to unconventional. Most importantly, these are the scripts that demonstrate how “screenwriting from scratch” is done.