Connecticut Yankee in King Arthur's Court

In the book, a Yankee engineer from Connecticut is accidentally transported back in time to the court of King Arthur, where he fools the inhabitants of that time into thinking he is a magician—and soon uses his knowledge of modern technology to become a "magician" in earnest, stunning the English of the Early Middle Ages with such feats as demolitions, fireworks and the shoring up of a holy well. ...