There is a ship traveling through space looking for a new earth type planet.
No one on board realizes it is a space ship, they believe they are living in a subterranean area hundreds of levels below a contaminated surface. No one is allowed to go up to a higher level for fear of releasing further contamination.
The ship has traveled for many generations, books were banned and reading became banned as well.
The main character has been taught to read by his father who has been taught by generations of his family. There is a secret hoard of reading book of all types to which the hero has access to read secretly.
Eventually the hero access the upper level of the ship, which turns out to be the control deck of the ship. All the information required to control the ship are written there for anyone to read and therefore complete their mission.
I saw it on television sometime during the 1960-1970 period.
Can anyone please identify the book title and the writer for me?