This chapter is dedicated to functions. First, we'll see some more advanced features of functions in Kotlin that we've not covered in Chapter 2, Kotlin Basics. Then, the rest of the chapter is dedicated to function types and lambdas. Lambdas and function types are an essential part of Kotlin, and the standard library relies on and uses them extensively. 

In this chapter, we will cover the following:

• Advanced functions
• Lambdas
• Function types