To get the most out of this book

All you need is a copy of Unity 2018, which can be downloaded for free from http://www.unity3d.com.
If you wish to create your own image files, for the recipes in the Creating Maps and Materials, for example, you will also need an image editor, such as Adobe Photoshop, which can be found at http://www.photoshop.com, or GIMP, which is free and can be found at http://www.gimp.org.