The book follows Oceanhouse Media's "omBook" format for ebooks in offering you three reading options: 'Auto Play' reads the book out loud, turning the pages as the story goes on; 'Read to Me' reads it out loud but lets kids turn the pages at their own pace; and 'Read It Myself' enables kids to handler the reading and the page turning on their own--without narration or automatic page-turning.

The app is extremely well executed, with gorgeous graphics and great sound effects. The text is crisp and easy to read, and words are highlighted in yellow as the narrator reads them aloud. Each "page" features wide-screen artwork, giving the app freedom to zoom in or out and to pan across the scene as the story progresses.

The scenes are also mildly interactive. When you tap on any of the creatures in the scene, their names (Tyrannosaurus rex, Ankylosaur, and so on) zoom up; if you pause the narration of the main story, the narrator also tells you the name of the specified animal. At the end of the main story, you can read (and listen to, if you like) background information on the Tyrannosaurus rex.

The background soundtrack is good, but not perfect. Most of the time it's just ambient noise, such as crickets chirping or water rushing, but occasionally the sounds get loud enough to drown out the narration. This could be a problem, especially because a lot of the words in the book are fairly complex Latin dinosaur names.

It's Tyrannosaurus Rex! is an almost-perfect Android e-book, and I recommend it for kids and adults alike. It's beautifully illustrated, it runs very smoothly, and poking dinosaurs to learn their names is all kinds of fun. Plus, it's a collaboration with the Smithsonian and comes packed with interesting facts and information.