The Google Daydream is one of the most powerful mobile VR systems available. With the right set of tools, developers can build applications that take advantage of its many features, which include head tracking, stereoscopic rendering, and spatial audio output. This book explores two of these toolsets: the Google VR Software Development Kit (SDK) for Android and the Google VR Native Development Kit (NDK) for Android. The Unity SDK and the Unreal SDK are not discussed.The book begins by introducing Android Studio and the fundamental classes provided by the Android API. Next, the book presents 3-D rendering with OpenGL ES and the graphical requirements needed to create a virtual reality environment. The last part of the book presents applications that take full advantage of the Daydream's VR capabilities. In addition to presenting Java-based applications, the later chapters explain how to improve performance with C/C++ code.