"Doomsday Book" by Connie Willis (Oxford Time Travel - Very well-done. Willis really gives the reader a vivid picture of how dirty, misogynistic, and primitive it was to live then. And how awful the Black Death really was!
An astonishing technique for recovering and cloning dinosaur DNA has been discovered. Creatures once extinct now roam Jurassic Park, soon-to-be opened as a theme park. Until something goes wrong.and science proves a dangerous toy.