I purchased the set as a goodie book (one book for each kid) for my son's bithday, to the children in his class and for the children who came to his birthday party. They love it and the parents appreaciate it as well.

dinosaurs before dark was a really good book i liked it when
jack found the gold metel and anny she acted like a dog that was
funny i also liked it when jack and anny flew on a dinosaur that was my favorite

I love the ninja book the best because they helped Jack and Annie cross the icy water. I'm 6 years old and these are the first chapter books i've read. My Mom even likes them.

I love all of the books.

Our 6 year old likes the stories, but keeps referring to the cover to try to get a picture of what is going on in the story. The various stories tie well together and help teach a bit along the way. The kids in the stories get to experience things (Dinosaurs, going to the moon etc) in way that helps with the imagination. The only caveat, there are few pictures, while this is the intent, a better job illustrating the stories would help younger readers as they transition from picture books to chapter books.