Ask HN: Resources for learning about cookies

I am going to be working on a project at my new job that requires me to know a lot about cookies. I want to learn as much as I possibly can, but I'm not finding a lot of quality information.

What resources would you recommend I take a look at? Also, are there are types of exercises/sample use cases that might be particularly useful? Finally, what kind of background info would you consider to be crucial to understanding cookies?

I am open to any and all suggestions and I appreciate your input!