Back in the first half of the 20th century getting a copyright required filing for it with the U.S. Library of Congress. A simple form filed would result in a 28-year copyright term. And, at the end of that term you could file again for a second 28-year term.
But in practice very few books or stories were worth the time filling out the renewal form, especially those short stories published in magazines and various pulp-fiction titles. Continue reading “Unknown public domain books…”