This book tells the fascinating story of air navigation. In the beginning, pilots found their way by comparing the landscape below with the map. Railroads became their 'iron compass'. Above the clouds, the pilot had to make proper corrections of his heading for the deflection by the wind. This was the hour of birth for mechanical instruments for solving the wind problem. Soon these instruments were complemented with a set of scales to calculate flight time, fuel consumption, corrected instrument readings, and many more. The description of these instruments and their principles is embedded in a narrative of their historical context and their ingenious inventors. Collectors of these instruments will find detailed descriptions of models and makers.