Paleontology is the branch of biology that studies forms of life that existed in former geologic periods, chiefly by studying fossils.
Paleontologists use almost all the branches of science to aid their quest to know more about Earth's early history. They are constantly updating, adding to and even discarding information. As new discoveries are made, palentologists must often reexamine their own results: "Does this new discovery agree with my own findings?"
Paleontologists generally don't make lots of money. Their reward is the joy of exploration and discovery. They love to share and compare their ideas and discoveries with other scientists and especially, us!