Book excerpt: The Ever-Changing Sky provides a comprehensive and non-mathematical guide to spherical astronomy. The reader is guided through terrestrial and celestial co-ordinate systems, time measurement and celestial navigation, to the prediction of the rising and setting of the stars, Sun and Moon. It focuses on the geometrical aspects of the night sky without using complex trigonometry. The book progresses to a general study of the Earth and sky, including the stars and constellations (with useful star maps provided), the motions and appearance of the Moon, tides and eclipses, the orbits of the planets and the smaller bodies of the Solar System (asteroids, meteors, meteorites and comets). Finally, there is a brief overview of atmospheric phenomena (including rainbows and haloes). This text will be invaluable to students taking courses in naked-eye astronomy, amateur and professional astronomers, as well as more general readers wanting to know how the night sky changes.