We gave the book as a gift to a three-year old, and he probably spent more time with the book than any one of the myriad electronic gadgets and oversized presents he got.
This book is a "must-read" for any Thomas fan.
The only downside I would say about this book is that some of the flaps are not as strong as others. My toddler has ripped off a few of them, but mostly because he is so enthusiastic about the book!