Chapter 1, the introductory chapter, outlines the development of psychotraumatology or traumatic stress studies, in which the author was also partly involved. It traces how it came about that the author Brave Heart and others have been presenting concepts on historical trauma since the early 2000s. An operationalized definition with two basic criteria and five consecutive criteria is presented. The following eight contexts from all parts of the world are presented and their selection justified. The first four are typical configurations of historical trauma because they fulfil all the criteria without exception. The last four historical traumas fulfil only some of the criteria, but are each particularly revealing, for example when it comes to the minimization of the victim narrative for political reasons. The method of the coupled scoping review for the book is explained and the target groups of readership are described.