Ada Lovelace

Ada Lovelace was an English mathematician who, working from Charles Babbage's designs for the Analytical Engine, wrote what is widely regarded as the first computer program — a method for the engine to compute Bernoulli numbers. But her deeper contribution was conceptual. Where Babbage saw a calculator, Lovelace saw a general symbol-manipulator: a machine that, given the right rules, might weave algebraic patterns "just as the Jacquard loom weaves flowers and leaves," and even compose music.

That leap — from numbers to arbitrary symbols — is the seed of everything computing became. She also warned, presciently, that the machine "has no pretensions to originate anything"; it can only do what we know how to order it to perform. A century before electronic computers, she had glimpsed both their power and their limits. She belongs to the history of programming.