After this chapter, you should have a good grasp of the object-oriented features of the Kotlin language. You should be comfortable with using classes, inheriting from them, and implementing interfaces. And if you have experience with some other OO languages, then you'll probably appreciate how Kotlin is less verbose and more readable than some of its competitors thanks to features such as data classes, primary constructors with properties, and class delegation.

In the next chapter, we will learn more about functions and see that they are first-class citizens in Kotlin.