Just found 2 books that my 4yo ds loved today, obsessed as he is with dinosaurs and beasts.
One is a "magic torch" book with black acetate pages of dinosaur pictures: you put a "torch" of white paper underneath to illuminate the various dinosaurs - ds asked me whether it was 'real magic mummy?' It's called Lets Look At Dinosaurs and is a Torch Light book published by moonlight publishing.
The other is called "A Night in the Dinosaur Graveyard" from Templar publishing and is full of realistic dinosaur holograms. Might be scary for younger ones but mine knows they're extinct and wasn't phased by the idea of dinosaur ghosts. Anyway, he loved them both - thought I'd pass it on in case there are other similarly interested out there.