Information from the Chessbase website:
ABC'S OF MIDDLEGAMES
Gary Gauthier explains all the basics themes with the help of selected master games. The games are annotated and explained in a way that makes it possible for even the rank amateur to follow, while graphic commentary enables you to grasp the main ideas at a glance. The sections on strategy and tactics lay the foundation for a deeper understanding of the middlegame. In a training database you can check your progress by solving practical positions and scoring points for successful attempts. Each chapter has a video clip with an introduction by GM Daniel King. Available in the following languages: English and German.