In Time Machines the acclaimed paleontologist Peter D. Ward takes us on a trip not to the future, but to the end of the dinosaur age - from 80 million to 65 million years ago - to illustrate the techniques modern scientists use to recover events of the deep past. From patterns in rock, scraps of fossilized bone, and traces of metal that, to the novice's eye, seem of little significance, scientists have discovered how to paint compelling pictures of our ancestral worlds. The methods geologists and paleontologists use - "time machines" - are as varied as the rock hammer and the thought experiment, comparative anatomy and the measure of sea levels, and DNA analysis and paleomagnetism. No single time machine recreates an entire picture of the past: Ward shows us that each is like a different color of brushstroke, by itself almost meaningless. Yet, when appropriately combined, a coherent, often beautiful, portrait of the deep past can emerge.