This book offers the first comprehensive study of weighing as an economic practice in early Mesopotamia and shows its deep impact on its society. Relying on the data of thousands of cuneiform sources analyzed first-hand, my aim is to provide an integral view on this remarkable phenomenon and to try to answer the questions when, how, and why it appeared, how it changed in the course of the 3rd millennium BC, and how it reflected and affected economic and social practices and relations. The history of this project goes back to 2010 when I started working on a doctoral thesis in an interdisciplinary research group Value and Equivalence: The Genesis and Transformation of Values from Archaeological and Anthropological Perspectives at the University of Frankfurt funded by the German Research Foundation (DFG). I am grateful to my advisors, Thomas Richter and Aage Westenholz, for their manifold support and the knowledge in the "dark arts" of cuneiform scholarship they have bestowed on me. I am indebted to my friends and colleagues in the research group Value and Equivalence for the prolific theoretical discussions and its coordinator, Annabel Bockern, for the abiding support. Although the thesis was completed by the end of 2013, the delay in its publication was due to several factors. First, I was involved in the publication of more than 700 early cuneiform texts, which appeared in monographic form in 2013 and 2017 respectively. Secondly, this hiatus provided me with the opportunity to look at the topic with a fresh eye. As a result, I have written this book anew without using a single sentence from the original thesis and restating numerous arguments and conclusions. This book cites only relevant data and discussions with a view to making it accessible and enjoyable to specialists and the general public alike. It is my pleasure to thank Gonzalo Rubio for his guidance throughout the publication process and anonymous reviewers for their valuable feedback. In acknowledging the help of others, I would also like to mention the manifold support of the following colleagues: