The book is a commented collection of sources on the history of social psychology. Its purpose is to stimulate reflections on one's own theoretical and practical activities through the study of documents from the history and prehistory of the field. In 30 sections, texts are presented that range from ancient Greece to more recent times. Each section is preceded by explanations regarding the significance and historical context of the respective text. In particular, works related to theory formation, contributions to the exploration of increasingly differentiated subject areas, the impact on various areas of society and practice, and the increase in interdisciplinary connections are discussed.