Alan Turing, master cypher and mathematician, leader of the team that broke the Enigma code, inventor of the first large scale computer and originator of the basic principles of artificial intelligence. Blackmailed into admitting his homosexuality, convicted and chemically castrated in 1952. Suspected suicide 1954. Born 100 hundred years ago, June 23rd this year.
Joan Clarke, the female mathematician who worked at Bletchley Park. I had vague memories about her from reading Turing's biography when I was in middle school, but the significance of what she did sticks with me much more now that I'm older.