I’ve been on the hunt for a good facial expressions book recently, and let me tell you, the options are endless! If you’re looking for something comprehensive, I’d start with Amazon—they’ve got everything from beginner guides like 'Facial Expressions: A Visual Reference for Artists' to advanced anatomy books. The reviews are super helpful, and you can often peek inside the book before buying.
For something more niche, check out specialized art stores like Blick or even Etsy, where indie creators sell unique references. Digital versions are great too—Scribd or Gumroad offer instant downloads if you’re impatient like me. Just make sure to read the descriptions carefully; some books focus more on animation, while others dive deep into realism.