Complex sentence: Samuel Thurston Williamson (1891--1962) was a journalist, biographer, and book reviewer who served as the first editor-in-chief of Newsweek magazine (1933--1938).
Split into simpler sentences: Samuel Thurston Williamson (1891--1962) was a journalist, biographer, and book reviewer. Williamson served as the first editor-in-chief of Newsweek magazine (1933--1938).