Unity 3 is an integrated authoring tool for creating 3D video games or other interactive content such as architectural visualizations or real-time 3D animations. Unity is similar to Director, Blender game engine, Virtools or Torque Game Builder in the sense that an integrated graphical environment is the primary method of development.
Unity - a multiplatform tool for game development, from the very beginning created to facilitate your creativity. Unity provides a comprehensive set of professional quality applications, and "quite accidentally" contains the most powerful engine this side of a million dollars.
Learn Unity 4 for iOS Game Development (Technology in Action) by Philip Chu English | 2013 | ISBN-10: 1430248750 | 300 pages | PDF + EPUB | 34 + 19 MB
Unity is an incredibly powerful and popular game creation tool, and Unity 4 brings even more great features, including Mechanim animation. Learn Unity 4 for iOS Game Development will show you how to use Unity with Xcode to create fun, imaginative 3D games for iPhone, iPad, and iPod touch.