You can download and build RxKotlin from GitHub (https://github.com/ReactiveX/RxKotlin). I do not require any other dependencies. The documentation on the GitHub wiki page is well structured. Here's how you can check out the project from GitHub and run the build:

$ git clone https://github.com/ReactiveX/RxKotlin.git
$ cd RxKotlin/
$ ./gradlew build

You can also use Maven and Gradle, as instructed on the page.

For Gradle, use the following compile dependency:

compile 'io.reactivex.rxjava2:rxkotlin:2.x.y' 

For Maven, use this dependency:

    <dependency> 
      <groupId>io.reactivex.rxjava2</groupId> 
      <artifactId>rxkotlin</artifactId> 
      <version>2.x.y</version> 
    </dependency> 

This book targets RxKotlin 2.x, so remember to use io.reactive.rxjava2 instead of io.reactivex.rxkotlin, as the latter one is for RxKotlin 1.x.

Now, let's take a look at what RxKotlin is all about. We will begin with something well-known and, gradually, we will get into the secrets of the library.