Book excerpt: As our nearest star, the Sun offers a unique opportunity to study stellar physics in action. Following the success of his previous books, Galaxies and The Stars, Roger Tayler presents the first full picture of how studies of the Sun and the solar system help us understand stars in general and other planetary systems. Using mathematics appropriate for advanced undergraduate students in physics, this textbook provides a broad and wide-ranging introduction to the Sun as a star. Succinct derivations of key results - such as the properties of spectral lines, the theory of stellar oscillations, plasma physics, magnetohydrodynamics and dynamo theory - are provided in a number of handy appendices, ensuring that the book is completely self contained. Altogether, this is an invaluable textbook for students studying the Sun, stars, the solar-terrestrial environment and the formation of planetary systems.