Complex sentence: Isaac Deutscher (3 April 1907--19 August 1967), British journalist, historian and political activist of Polish-Jewish birth, became well-known as the biographer of Leon Trotsky and Joseph Stalin and as a commentator on Soviet affairs.
Split into simpler sentences: Isaac Deutscher (b.3 April 1907--19 August 1967) was a British journalist, historian and political activist of Polish-Jewish birth. He became well-known as the biographer of Leon Trotsky and Joseph Stalin and as a commentator on Soviet affairs.