The central theme of the 21 essays collected here and written between 1989 and 2019 is Ancient Mesopotamian Mathematics - its techniques and concepts, but also its historical dynamics and its influence on later Greek and Arabic (and thus to later European) mathematical reasoning. In addition, the first essay deals with historical dynamics in the field of language and argues that the Sumerian as a language originated from a creole language of the slaves of the late fourth millennium and only thereafter developed into the elaborate Sumerian language attested in the late 3rd Millennium BCE.