Almost every day we are challenged by new information from the outermost reaches of space. This text explores the physical principles that govern the workings of our world and the cosmos, on the largest and smallest scales - from bands of colour in a sunlit crystal to the spectrum of starlight in giant telescopes, from the arc of a hard-hit baseball to the orbit of the moon, from the ups and downs of a yo-yo to the universal laws of motion. Scientists put the principles of physics into action when they explore the universe with space probes, Earth-bound and orbiting telescopes, and experiments that mimic nature's conditions in the laboratory. They understand what they observe in distant galaxies through the application of universal laws. The authors show how these same principles operate in our daily lives. Many of our day-to-day experiences, in our kitchens and backyards, are microcosms of cosmic processes. Photography and original diagrams expand and enrich the text.