Here are entered works on mechanical, electromechanical or electronic discrete-state counting devices operating on any given number base, consisting of any combination of sensing, accumulating and readout elements, and being used as components in meters, automata and control systems. Works on manual or other counters for arithmetic processes are entered under the specific name, e.g. [Abacus,] or under the subject, [Mathematical instruments.] Works on devices which detect and measure radiation are entered under [Nuclear counters] or the specific name, e.g. [Scintillation counters.]