This technique of animation is very important to it's history. I am sure that many animated films could never have been made with out it. So that is why I decided to make an episode dedicated to it. Here are some resources if you want to learn more.
https://www.fleischerstudios.com/origins.html
https://www.lambiek.net/artists/f/fleischer_max.htm
https://tvtropes.org/pmwiki/pmwiki.php/Creator/MaxAndDaveFleischer
https://www.masterclass.com/articles/rotoscope-animation-guide#6-films-that-use-rotoscoping
https://www.youtube.com/watch?v=ROqlhMEWA70
https://www.studiobinder.com/blog/what-is-rotoscope-animation-definition/