Ethel Lilian Voynich, nee Boole (May 11, 1864–July 27, 1960) was an Irish writer and a supporter of several revolutionary causes. She was born to the mathematician, George Boole, and the feminist philosopher Mary Everest,who was the niece of George Everest. Ethel's husband was Wilfrid Michael Voynich, a Polish revolutionary, antiquarian, and bibliophile.