Professor Rindler explains the concepts with clarity and rigour while minimising the complexities of the notation and formulae. His ability to put ideas into words is outstanding. If you have heard the tales of trains that whoosh past in the ether, and are still none the wiser; or have wondered how the background radiation that set out on its way at the speed of light when the world was a smaller simpler place is only now reaching us, this book will enlighten you. Even for those whose maths cannot keep up it should be worthwhile, stimulating even, to read the sections at the beginning of each chapter, and those elsewhere light in formulae. For those willing to tackle the exercises he is perhaps a little too generous with the hints.