Dear Reader! With this book I would like to proof my dear teacher's and mentor's, Prof. Rudolf Slavicek's thoughts about the Centric Relation which was named by him to Reference Position. The 3D relationship between maxilla and mandible is the most important step in our diagnosis, initial therapy and definition of our later therapeutic position. Different clinical cases require different bite registration methods to achieve a neuromuscularly stable reference position. The challenge in our daily practice is to use the right concepts with the right methods. But are they than really reproducible?