<p>On a clear and moonless night, especially in remote areas such as deserts, myriads of points of light cover the sky. The great majority of them are stars, many like the Sun, but so far away that they can only be seen as point sources of light. The problem faced by astronomers is to find their properties and distances, just from the light they emit. This is done by using the knowledge of science, mainly physics, acquired from small-scale experiments carried out on Earth. However, the stars themselves are laboratories in which matter behaves in ways that cannot be reproduced on Earth so, in finding out about stars, we complement scientific knowledge gained from earthbound experimentation.</p><p>This book describes the means &mdash; some very ingenious &mdash; by which to explore the properties, locations and planetary companions of stars, and provides a sound foundation for further study.</p>