Pafnuty Lvovich Chebyshev
A limping Russian nobleman's son who proved a bound so general it needs no assumptions about the shape of your data, then spent his evenings designing a mechanical bicycle for women
Pafnuty Chebyshev proved a strikingly general, distribution-free bound on how far a random variable's values can stray from its mean -- now known as Chebyshev's inequality -- while also proving Bertrand's postulate about prime numbers, coming close to the Prime Number Theorem, and founding the general theory of orthogonal polynomials. This bio covers his childhood limp and its role in his early scholarly focus, his insistence on being a 'world-wide' rather than merely Russian mathematician, and his parallel career designing mechanical linkages, calculating machines, and a bicycle for women.