Ask HN: Professional CSS books and tutorials?

I am currently reading this book http://www.amazon.com/Pro-CSS-Techniques-ebook/dp/B001DA0FII/ref=pd_sim_kinc_2?ie=UTF8&m=AG56TWVU5XWC2 and enjoyed it. I also enjoyed yesterdays post on selectors, However, I am looking for more information on CSS's best practices and details of implementation. Any books or links?