Welcome to YT!
and IMO...
You'll learn way more on YT just by reading old and new threads than I think you will learn in books. I have a book that was given to me when I got Oscar and I found it gave only very general information about the breed, general care, and breed history. On here, you get REAL answers to specific questions from a ton of people. Even if you don't have your yorkie yet, people will be more than willing to answer your questions - and it's nice to get opinions from several people. You'll learn things that you never would have even thought and that you'll never find in just one book. IMO, you should save your money and research what you can on internet search engines and here on YT.