Cardano, Girolamo or Geronimo(jērô`lämō kärdä`nō, jārô`nēmō), 1501–76, Italian physician and mathematician. His works on arithmetic and algebra established his reputation. Barred from official status as a physician because of his illegitimate birth, he practiced as a medical astrologer. His major work, De subtilitate rerum (1550), on natural history, is perceptive and implies a grasp of evolutionary principles. His book on games of chance represents the first organized theory of probability. Cardano described a tactile system similar to Braille for teaching the blind and thought it possible to teach the deaf by signs.
See his The Book of my Life (1643, tr. 1930); studies by O. Ore (with a tr. of Cardano's Book of Games of Chance, 1965) and A. Wykes (1969).