Wind is one of the fundamental aspects of man’s environment. In many ways, it is vital to our existence: it diffuses and removes local concentrations of pollutants and transports substances vital to life; it redistributes latent and sensible energy which fuel our weather systems; and historically it has been important as an energy source, both on land and sea. At the same time, its capacity for destruction is immense. Hurricanes, tornadoes, and fohn winds are some of the more obvious manifestations of its destructive fury, but even more commonplace storms can inflict considerable damage if the design or construction of structures does not adequately take into account the forces inflicted by the wind. In the following paragraphs, I shall describe the forces that produce and dissipate winds, the character of its essential turbulence, its variation with height and wave number, its frequency distribution, and its effects on structures.