Astrophysics is said to have been born when Isaac Newton saw an apple drop in his orchard and had the electrifying insight that the Moon falls just like that apple. James Binney shows how the application of physical laws derived on Earth allows us to understand objects that exist on the far side of the Universe. an enjoyably easy read, and a long way from being a stodgy textbook - I mean, what textbook would tell you the Galaxy contains 'zillions of dark-matter particles'?