Special Theory of Relativity (Translated From the Russian By Yuri Atanov)

All natural phenomena happen in space and in the course of time, and an element of any phenomenon is something occuring at a given moment of time and at a given point in space. In the special theory of relativity it is customary to refer to that "something" taking place at a given point and at a given moment of time (in fact, something concentrated in a sufficiently small volume of space and limited by a small time interval) as an event.