This is an interesting novel, written by two authors, William Gibson and Bruce Sterling, principally known for their work in the cyberpunk genre. The Difference Engine however is an alternate history story based on steampunk ideas.

The basic premise of the novel is that Charles Babbage's general purpose mechanical computer (which in reality was called the "Analytic Engine" - the real-life Difference Engine was a mechanical calculator) was not only successfully created, but widely adopted. Thus Victorian England, experiences something akin to the late 20th century's information technology revolution. Furthermore, Britain is ruled by the "Industrial Radical Party", which places a great emphasis on industry, science and technology, leading to an even more powerful British Empire than experienced in our timeline.

The plot, such as it is, basically concerns the hunt for some extremely powerful punched cards (used to program Babbage's computers). While it would be incorrect to say that there isn't a story - there clearly is - the real joy of the novel comes more from the wealth of detail and the well-realized alternate world, than the plot.

I am sure that William Gibson's and Bruce Sterling's many fans will snap up the book regardless of anything that I might say. That said, my own personal view, is that while I enjoyed reading the novel (and would recommend it to others), I didn't enjoy quite as much as some other steampunk novels that I have read - the reason is, for me, the plot was not interesting enough, even though the background of the world was beautifully portrayed.