Book excerpt: In today’s world of online maps and travel directions delivered wirelessly to hand-held devices, getting from place to place requires little thought from most of us—which is a good thing, since accurate navigation can be tricky. Get your bearings with Mark Denny—an expert at explaining scientific concepts in non-technical language—in this all-encompassing look at the history and science of navigation. Denny’s tour kicks off with key facts about the earth and how its physical properties affect travel. He discusses cartography and early mapmakers, revealing fascinating tidbits such as how changes over time of the direction of true north, as well as of magnetic north, impacted navigation. Denny details the evolution of navigation from the days of coastal piloting to GPS and other modern-day technologies. He explains the scientific breakthroughs in accessible, amusing terms and provides an insightful look at their effects on societies, cultures, and human advancement. Throughout, Denny frames the long history of navigation with amazing tales of such people as Pytheas, an ancient Greek navigator, and Sir Francis Drake and of such discoveries as the magnetic compass and radio direction finding. Whether you have an interest in orienteering and geocaching or want to know more about the critical role navigation has played in human survival and progress since ancient people learned to use lodestones, The Science of Navigation is for you. With it you’ll finally understand the why of wayfinding.