Delphi methods enable the systematic collection of expert judgments. They have proven to be particularly useful when a certain level of expertise and judgment is required to answer a research question. There are different variants of Delphi methods, such as the group Delphi or the real-time Delphi. The book presents current methodological developments and examples of application in the social and health sciences. The contents Delphi methods: Concepts and variants - Epistemological discussion - Practical challenges - Delphi in the social and health sciences - Real-time Delphi - Delphi markets. Application examples for Delphi methods - Qualification requirements, recommendations for action for further development and strategy development in the health care industry - Personnel retention and recruitment in occupational nursing - Group Delphi for obesity prevention- Safety and health competence at work - Delphi methods in health promotion The editors Prof. Dr. Marlen Niederberger is professor for research methods in health promotion and prevention at the PH Schwbisch Gmnd. Prof. Dr. Ortwin Renn is Scientific Director at the Institute for Advanced Sustainability Studies, Potsdam (IASS). This book is a translation of the original German 1st edition Delphi-Verfahren in den Sozial- und Gesundheitswissenschaften by Marlen Niederberger and Ortwin Renn, published by Springer Fachmedien Wiesbaden GmbH, part of Springer Nature in 2019. 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 tosupport the authors.