Everyone knows what a dinosaur is, right? Well, maybe not. Roaming the earth alongside dinosaurs, there were other less well-known animal species - but they were not dinosaurs. So, what is it that sets the dinosaurs apart? Here, readers are introduced to ten prehistoric animals that look like dinosaurs, but they're missing at least one key characteristic that all true dinosaurs have. One by one, each of those 'missing' characteristics is added to a growing list, so that, by the end of the book, readers will know what makes a dinosaur a dinosaur!