"There is grandeur in this view of life, with its several powers, having been originally breathed by the Creator into a few forms or into one; and that, whilst this planet has gone cycling on according to the fixed law of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being evolved."

-- Charles Darwin, ON THE ORIGIN OF SPECIES, 6th ed., p. 429

Many of my books about fossils don't limit themselves to any particular period or any one group of life-forms. Instead, they deal with paleontology in general and the entire grand sweep of life on Earth.