From 1909 to 1930, U.S. courts grappled with claims by authors of prose works claiming that works in a new art form—silent movies—had infringed their copyrights. These cases laid the groundwork for much of modern copyright law, from their broad expansion of the reproduction right, to their puzzled grappling with the question how to compare works in dissimilar media, to their confusion over what sort of evidence should be relevant to show copyrightability, copying and infringement. Some of those cases—in particular, Nichols v. Universal Pictures—are canonical today. They are not, however, well-understood. In particular, the problem at the heart of most of these cases—how to imagine a work consisting entirely of pictures as infringing a work made entirely of words—has largely vanished from our consciousness. A better understanding of these early cases casts into clearer doctrines and practices we take for granted today.
Litman, Jessica D. "Silent Similarity." Chi. -Kent J. Intell. Prop. L. 14, no. 1 (2015): 11-47.