As most of us already know, gestures are quick, rough and often times rough sketches of what an artist observes.  It is pretty much the hand translating what the eye sees, without worrying about size, scale and so much detail as much as getting the basic idea, impression, pose, silhouette (this all depends on what you are gesturing) down.  Gestures most of the time act as pre pro to some better more finished and more appealing art work.  However, they are an important preparation that is seldom overlooked.