Fifty years ago, it would have seemed strange for a paleontologist to write a book about birds, but today we know why the pairing makes sense. Birds are dinosaurs: it’s as literally true as saying humans are mammals. The brontosaurus and the triceratops might have been wiped off the face of the planet 66 million years ago by an asteroid the size of Mount Everest — just about anything bigger than a dog was — but the dinosaurs never really went away. There are probably a few perched outside your window right now, gathering twigs, hunting insects, and chirping.