Timeline by Michael Crichton

Timeline is a science fiction novel by American writer Michael Crichton, his twelfth under his own name and twenty-second overall, published in November 1999. It tells the story of a group of history students who travel to 14th-century France to rescue their professor. The book follows in Crichton's long history of combining science, technical details, and action in his books, this time addressing quantum and multiverse theory.