First published in 1925, Bertrand Russellβs ABC of Relativity was considered a masterwork of its time, contributing significantly to the mass popularisation of science. Authoritative and accessible, it provides a remarkable introductory guide to Einsteinβs theory of Relativity to a general readership. One of the most definitive reference guides of its kind, and written by one of the twentieth centuryβs most influential philosophers, ABC of Relativity continues to be as relevant today as it was on first publication.