Steven Holzner does a wonderful job of starting with the very basics of RSS and moving onto more advanced topics towards the end of the book. He covers RSS Feeds, RSS Readers, Blogging with RSS, Podcasting, Publicizing your feeds, RSS Best Practices, and a few other topics.
The book is well-written and easy to read, and well-designed (something I've found with all of Peachpit's titles. While most folks won't be interested in the details of creating a feed by hand, or the subtle differences between versions of the RSS standard, these tidbits ensure the book is a complete treatment of the subject.
For $15 (here on Amazon) you're not going to find a better look at RSS.