I have recently taken the reigns and am working very hard on a new book, Angular in Action. Writing a book is a major effort, and I’m already near the half way mark. If you grab a copy of the book, please go to the forums as well and report back any thoughts!
The book has actually been in production for a while now, but skipping ahead things have been rebooted (and rewritten) so that the content reflects the reality of Angular today. The book focuses on Angular 2 and above. Since Angular has moved to a new versioning scheme, it doesn’t make sense to say Angular 2 anymore.