I saw this very interesting article on the March 2026 AMS Notices and thought to share here:
https://www.ams.org/journals/notices/202603/noti3305/noti3305.html
Summary: First posed by Francis Guthrie in 1852, the four-color problem was eventually answered in 1976 by Kenneth Appel and Wolfgang Haken, when it became known as the four-color theorem. To mark its 50th anniversary, this article recounts the story of the proof, focusing particularly on the individuals involved.
