Pickaxe Book, Chapter 12 - but it is terser and aimed at someone with more experience. I think that the article is a good introduction to Threads, and once you

Pickaxe Book, Chapter 12 - but it is terser and aimed at someone with more experience. I think that the article is a good introduction to Threads, and once you understand how they work, then Fibers and Ractors start to become easier to understand.