This book is intended for undergraduates taking an introductory course on special relativity which is rather more conceptually and mathematically than experimentally orientated. A suitably prepared reader could use it for self-study. It assumes no prior knowledge of relativity. Thus it elaborates the underlying logic, dwells on the subleties and apparent paradoxes, and also contains a large collection of problems which should just about cover all the basic modes of thinking and calculating in special relativity. Much emphasis has been laid on developing the student's intuition for space-time geometry and four-tensor calculus; but the approach is not so dogmatically four-dimensional that three-dimensional methods are rejected our of hand when they yield a result more directly. This updated new edition contains additional examples and problems, and the chapter on relativistic mechanics of continua has been substantially rewritten.