Simplify the following text for a Grade 5 native English-speaking person.
Original: John Ernst Steinbeck ( February 27 , 1902 - December 20 , 1968 ) is a very famous American writer of the 20th century .
Simplified: John Ernst Steinbeck , Jr. ( February 27 , 1902 â `` December 20 , 1968 ) was an American writer .