Bertrand Russell - "Bertie" as his friends called him - is hard to peg down as to what was his real avocation, what was his most important legacy, and even what era he was from. Before World War I, he was an internationally known logician and mathematician. After World War I, he was a philosopher and educator, and shortly after World War II, he won the Nobel Prize in Literature. By the time the 1960's rolled in, he was an anti-war and disarmament activist, who had earlier, somewhat paradoxically and to his later embarrassment, advocated pre-emptive nuclear war with the Russians.
Well, you can do an awful lot during your life if you can make it past your 97th year.
His "History of Western Philosophy" (published in 1945) is still pretty good reading although (naturally) a bit out of date.
Charcoal on Bristol Board