Kotlin comes to solve the real-world problems of today. In the following chapters, we will discuss both Design Patterns first introduced by the Gang of Four back in '94, as well as design patterns that emerged from the functional programming paradigm.

You'll find that some of the design patterns are so common or useful that they're already built into the language as reserved keywords or standard functions. Some of them will need to combine a set of language features. And some are not so useful any more, since the world has moved forward, and they're being replaced by some other patterns.

But in any case, familiarity with design patterns and best practices expands your "developer toolbox" and creates shared vocabulary between you and your colleagues.