Book excerpt: This book shows how the science of geomagnetism contributes to effective use of the magnetic compass for navigation. The book uses techniques from Geology, Instrument science, Magnetism, Chaos theory and Potential Fields applied to the geomagnetic landscape of the Balkan region and surroundings. The editors and contributors have assembled a comprehensive review of measurement, analysis, mapping and forecasting of magnetic declination in support of aeronautical safety.