Ada, Countess of Lovelace (1815­-52), daughter of romantic poet Lord Byron and the highly educated Anne Isabella, is sometimes called the world's first computer programmer, and she has become an icon for women in technology today. But how did a young woman in the nineteenth century, without access to formal schooling or university education, acquire the knowledge and expertise to become a pioneer of computer science? Although it was an unusual pursuit for women at the time, Ada Lovelace studied science and mathematics from a young age. This book uses previously unpublished archival material to explore her precocious childhood--from her curiosity about the science of rainbows to her design for a steam-powered flying horse--as well as her ambitious young adulthood. Active in Victorian London's social and scientific elite alongside Mary Somerville, Michael Faraday, and Charles Dickens, Ada Lovelace became fascinated by the computing machines of Charles Babbage, whose ambitious, unbuilt invention known as the "Analytical Engine" inspired Lovelace to devise a table of mathematical formulae which many now refer to as the "first program." Ada Lovelace died at just thirty-six, but her work strikes a chord to this day, offering clear explanations of the principles of computing, and exploring ideas about computer music and artificial intelligence that have been realized in modern digital computers. Featuring detailed illustrations of the "first program" alongside mathematical models, correspondence, and contemporary images, this book shows how Ada Lovelace, with astonishing prescience, first investigated the key mathematical questions behind the principles of modern computing.