Creating our own operators and resource-dependent Observable instances gives us unlimited possibilities when it comes to creating logic around the Observable class. We are able to turn each data source into an Observable instance and transform the incoming data in many different ways.

I wanted this book to cover the most interesting and important parts of RxJava. If I have missed something important, the documentation at https://github.com/ReactiveX/RxJava/wiki is one of the best on the web.. Refer especially to this section for further reading: https://github.com/ReactiveX/RxJava/wiki/Additional-Reading.

I have tried to structure the code and the ideas and to provide them in small iterations over the chapters. The first and second chapters are more ideological; they introduce the reader to the basic ideas of the functional programming and the reactive programming and the second chapter tries to establish the the origins of the Observable class. The third chapter provides the reader with the means to create a variety of different Observable instances. The fourth and fifth chapters teach us how to write logic around those Observable instances and the sixth adds multi-threading to this logic. The seventh chapter comes with unit testing the logic that the reader has learned to write and the eight tries to extend the capabilities of this logic even further.

I hope you, the reader, found this book useful. Don't forget, RxJava is just a tool. The important things are your knowledge and your thinking.