BERTRAND RUSSELL ABC OF RELATIVITY

This book first appeared in 1925. The basic principles of relativity have not changed since then, but both the theory and its applications have been much extended, and some revision has been necessary for the second and subsequent editions. For the second and third editions I carried out these revisions with Bertrand Russell's approval. The revisions for this fourth edition are entirely my responsibility. I have again altered a number of passages to agree with present knowledge or opinion, and I have attempted to eliminate the possessive case, as applied to laws or theories, where it seemed to me no longer appropriate....