This book can be read without a computer or laptop at hand, in which case you need nothing more than the book itself. However, to follow the examples in the book, you need Java 8, which you can download from http://www.oracle.com/technetwork/java/javase/downloads/jdk8-downloads-2133151.html, and you will also need your favorite IDE. I have used the Software Spring Tool Suite; download the latest version of Spring Tool Suite (STS) from https://spring.io/tools/sts/all according to your OS. Java 8 and STS work on a variety of platforms—Windows, macOS, and Linux.