Complex sentence: Leon Marcus Uris (August 3,1924--June 21,2003) was an American author of historical fiction who wrote two bestselling books "Exodus" (published in 1958) and "Trinity" (published in 1976).
Split into simpler sentences: Leon Marcus Uris (August 3,1924--June 21,2003) was an American author, known for his historical fiction. His two bestselling books were "Exodus" (published in 1958) and "Trinity" (published in 1976).