Before the Copyright Act of 1976 (effective as of 1978), copyrights were only good for a maximum of 56 years: a first term of 28 years and renewable for another 28. However, the Copyright Act of 1976 made it so that the copyright on original works would last until the end of the author's life + 70 years. So, all of that film, music, and other types of art you could have used from 1958 without fear of getting sued will have to wait just a bit longer. Have a safe and happy Public Domain Day!
What are you favorite public domain works?