The book is about how attributes actually work in Python. I start with some simple examples using the done there get after a special method that allows you to emulate like a virtual attribute. Then I talk about properties in the, and then I go to the next chapter is about descriptors, which is the infrastructure for properties. And then I developed an example that was that evolved from a talk that I gave at Python in 2013 in Santa Clara. Was called encapsulation with descriptors,. But in the chapter I can spend much more than 45 minutes with that or 30 minutes action it was. The last chapter is about class method programming. That's that wraps up the book.