This chapter has established that we can model asynchronous events as values on a time axis. We introduced the idea of comparing these streams to lists and thereby applying functional methods to them that would not change the lists themselves but merely create a new list. The benefit of applying the functional paradigm is that we can focus on what to achieve rather than how to achieve it, thereby having a declarative approach. We realize it's not easy to combine async and lists and create readable code from it. Fortunately, this is what the RxJS library does for us. It is this realization that prepares us for the coming chapter, Chapter 5, RxJS Basics, where we introduce RxJS as a library just that: create order in the async mess while modeling everything as a stream. With RxJS, we can truly focus on what rather than how, as it comes with a bunch of stream manipulation functions. After having read the next chapter, you will understand how RxJS works on a fundamental level, but also how it addresses the problems mentioned in this chapter.