Complex sentence: John Gibson Lockhart (12 July 1794--25 November 1854), Scottish writer and editor, is best known as the author of the definitive "Life" of Sir Walter Scott.
Split into simpler sentences: John Gibson Lockhart (12 July 1794--25 November 1854), was a Scottish writer and editor. He is best known as the author of the definitive "Life" of Sir Walter Scott.