What are executive functions? Can these be improved in children between 8-9 years of age through complex working memory training? What role do different types of stress processing play in relation to training performance? Is there any connection at all between cognitive and emotional self-regulation in children and how does this manifest itself? After a theoretical overview of the constructs of working memory, executive functions and stress processing, this textbook deals with the results of an empirical training study in which ninety-two eight- to nine-year-old children from Switzerland took part for four weeks. The results indicate a connection between cognitive and emotional processing and control techniques that are important for school careers and personality development.