Five autographs: member-card signed by Helen Keller, an American author and social activist; postcard from Albert Schweitzer, a German-French theologist, musician, philosopher and doctor, winner of a Nobel Prize in 1952; letter signed by Christiaan Neethling Barnard, a South African heart surgeon who performed the world's first heart transplant; a signed letter from Jonas Edward Salk, a Jewish-American doctor and virologist, who invented the polio vaccine; a card signed by Niels Bohr, a Danish physicist of Jewish origin, winner of the Nobel Prize in physics. Sizes and conditions vary.