‘A brief history’ shows that measurement is at least as old as civilization. Different systems and different units of measurement were developed in different places, with the physical size of natural biological objects frequently being used as a basic unit. The key drivers for a uniform measurement system were trade, the industrial revolution, and scientific advance. In 1960 the Système International d’Units (SI units) was introduced, consisting of seven basic units: length (metre), mass (kilogram), time (second), electric current (ampere), temperature (degree kelvin), quantity of substance (mole), and luminous intensity (candela). Another twenty-two named units were defined as powers and combinations of these basic seven.