It is a common misconception that the Shawshank Redemption film was taken from a book of a similar name by Stephen King. Stephen King did write it, but it was a novella called ‘Rita Hayworth and Shawshank redemption’ in a book called Different Seasons, which he wrote in 1982 and is still in publication today.
The film follows the book very closely, the plot or story line is very similar, and as in the film, the book is narrated by Red.
This Novella is widely appreciated as one of Stephen Kings best pieces of writing, maybe due to the popularisation through film, however, it is indeed a great piece.
The book tends to give a better feeling of the passage of time than the film, probably for obvious reasons that the film has to capture and take it audience along throughout a limited run time, where as the book can allow its reader to come and go, while still maintaining the thread of the story. Having said that the Novella is only 106 pages long (depending on the version), so this is not a long read at all.