This book helps professionals deal with difficult or even dangerous colleagues, employees or superiors. Some people poison the working atmosphere, make other people ill and cost their companies a lot of money. Often the cause lies in a psychological disorder, we are then often dealing with narcissists or psychopaths, but usually the destructive behavior is not (yet) based on a psychological disorder. This book introduces a collective term for such people - it calls them "toxic people" - and helps both those affected and those responsible in companies and organizations to recognize them, to protect themselves and others from them, and to take promising action against them. In addition to information on the typical characteristics of "toxic people," their motives are explained and concrete strategies for action and examples of tried-and-tested assistance are provided. A new chapter provides vivid, exciting case studies from real-life situations. A book for managers and those affectedas well as personnel developers, trainers, consultants and coaches in companies and organizations. This book is a translation of the original German 2nd edition Schwierige Menschen am Arbeitsplat by Heidrun Schüler-Lubienetzki and Ulf Lubienetzki, published by Springer-Verlag GmbH Germany, part of Springer Nature in 2017. The translation was done with the help of artificial intelligence (machine translation by the service DeepL.com). A subsequent human revision was done primarily in terms of content, so that the book will read stylistically differently from a conventional translation. Springer Nature works continuously to further the development of tools for the production of books and on the related technologies to support the authors.