Dinosaurs are fascinating animals for children's imaginations to grasp and run away with. They are real, but not real at the same time. Children know they are real because adults tell them that dinosaurs existed and we have bones and models to show them. The dinosaurs are fascinating because they look and behave very differently from people (some eat meat, others eat plants, some can fly, some have short arms and long legs, some swim, and they can be huge, or very small.)
But since they do not live in this age, in their original form (either due to evolution or extinction), it frees the child from truly being afraid of these sometimes gigantic fearsome relics. Children's books with dinosaur themes, almost always centralize on a dinosaur becoming a child's friend or pet. Books that lack people and only show dinosaurs, put forth the idea that dinosaurs hurt other dinosaurs, not people. The dinosaurs are thus, real, but not real for children.
It can be difficult to assemble a collection of classic books on any topic, this writer has picked out dinosaur classics that are worthy of passing down to the next generation of children. Please be warned, several books are old enough that they are now out of print and may need to be purchased via ebay and other sources.