<P>First published in 1925, Bertrand Russell¿s <EM>ABC of Relativity</EM> 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 Einstein¿s theory of Relativity for a general readership. One of the most definitive reference guides of its kind, and written by one of the twentieth century¿s most influential philosophers, <EM>ABC of Relativity</EM> continues to be as relevant today as it was on first publication.</P>