Over 150 years after her death, a widely-used scientific computer program was named "Ada," after Ada Lovelace, the only legitimate daughter of the eighteenth century's version of a rock star, Lord Byron. Why? Because, after computer pioneers such as Alan Turing began to rediscover her, it slowly became apparent that she had been a key but overlooked figure in the invention of the computer. Essinger makes the case that the computer age could have started...