The letterbox format has the famous "black bars" on a standard fullscreen (4:3) television set. This is a result of the original widescreen image being shrunk down to fit your television screen, without losing any of the original image, unlike the pan and scan method. There is a common misunderstanding that when you see the "black bars" at the top and bottom of the television screen, you're not getting the whole picture. People believe that for some unknown reason, the top and bottom of the image was purposely blacked out to hide stuff from you. This is not true. Not only are you seeing everything, but you get the added bonus now of viewing the side material that was otherwise cut off when the theatrical movie was transferred to standard television.
In most cases, depending on the formatting of the film, the black bars in a letterboxed movie or TV show are not seen when the movie or show is seen on widescreen TV sets (in the 16:9 format, displayed as either 1.77:1 or 1.85:1). In the anamorphic widescreen (CinemaScope) format of 2.35:1 common with some feature films, however, the black bars still appear on widescreen TVs unless the TV set is built to fit the 2.35:1 format.