Complex sentence: Thomas Sterling North (November 4,1906--December 21,1974), who used Sterling North professionally, was an American writer, probably best known for the children's novel "Rascal", a bestseller in 1963.
Split into simpler sentences: Thomas Sterling North (November 4,1906--December 21,1974), who used Sterling North professionally, was an American writer. He is best known for the children's novel "Rascal", a bestseller in 1963.