Precision and uniformity are indispensable when working with physical quantities, units and formula symbols. Only through unambiguous and authoritative notation is interdisciplinary cooperation possible. The book gives an overview of all common quantities and units, which are needed in studies and teaching as well as in everyday work. All printed quantities and units are currently valid and standardized in ISO/IEC. The book includes: _brief introduction to the development of the system of units _overview on the system of quantities and units _calculating with quantity values _units (international system of units, SI) _notation of numbers _mathematical symbols _Standardized symbols for quantities (mechanics, space and time, radiation, solid state physics, etc.), elements, nuclides, particles and quantum states. _Appendix: conversion to the U.S. customary system of units.

_Studied physics and mathematics at the Technical University of Berlin; Doctor of Science in Physics; Habilitation; _Senior Scientist (retired) of PTB (the German National Metrology Institute); until 2022 Chair of IEC TC 25 "Quantities and Units"; project leader for the last revision of the ISO/IEC 80000 series of standards in ISO TC 12 "Quantities and Units", member for PTB in the BIPM-CCU, expert for ISO and IEC in the JCGM working groups for VIM and GUM; _Author of 5 books, several book chapters, and more than 160 scientific journal articles; _Research Interests: Fundamentals and mathematical methods of metrology, measurement data evaluation, measurement uncertainty, history of mathematics and physics;