Because of its complex nature, the knowledge of spread F is not commensurate with the long period of its study. Rockets, satellites and radar systems have greatley advanced observational information on spread F. We have outlined some of these observations and presented information on certain morphology and characteristics of both the equatorial and high latitude spread F. Although the study of the equatorial spread F seems more advanced than the study of the high latitude spread F, the causes and mechanisms of spread F are poorly understood.