Something written long ago by Eric Raymond, dense but relevant
https://mijowa.github.io/CatB/
Richard M Stallman is a good person to research
https://www.gnu.org/philosophy/floss-and-foss.en.html
A good basic overview
https://opensource.com/resources/what-open-source
A view from the creator of the Linux kernel, Linus Torvalds
https://www.linux.com/news/linus-explains-why-open-source-works/