The Difference Engine is a 1990 novel by both William Gibson and Bruce Sterling. It is an "alternative history" book, and is notable for how it pioneered and helped establish the steampunk genre. The novel was nominated for a number of awards, including but not limited to the Nebula Award for Best Novel and the Prix Aurora Award.
The novel focuses around a very different Victorian England, one transformed by significant technological and social change after the invention of a mechanical computer named the "Difference Engine". The inventor, Charles Babbage, goes on to design an "Analytical Engine", and in time, becomes politically significant. The novel centers around the widespread effects of Babbage's computers as they go on to form an entirely new future from what we know today.
The Difference Engine was nominated for a great amount of awards. It was also generally well-received by critics. However, scholars have appointed it the greatest significance for helping to define the steampunk genre and its modern day characteristics.