This book is about drivers of successful controllership. Successful controllership services provide an imperatively required support to managers,especially in times of change. But what makes controllership services successful? Our book provides the fi rst comprehensive set of answers to thisquestion. We argue it is not the selection of latest tools and techniquesbut carefully customized services, motivated and skilful employees, andintensive mutual exchanges with managers and open cooperation withother internal service providers. Our book thus addresses managers whowant to learn how they best profi t from a close collaboration with controllers,and controllers who strive to improve the quality of their servicesto deliver superior performance.