Book excerpt: This easily accessible description charts the historical development of magnetism - dating back some three thousand y ears. Alberto P. Guimaraes starts with the Greeks, with the first records of magnetism, and ends with hard disks and magnetic resonance imaging. Nowadays every electric and electronic device involves the use of magnets, such that magnetic devices, including magnetic media and recording equipment, represent a world market of over 100 billion dollars each year. Enjoyable reading for graduates, physics students, libraries, public libraries, school libraries, those interested in the natural sciences, lay readers, historians of physics.