Parents know—at six months old or so, everything goes into the mouth! Fortunately, the teether included here can—and by this age, babies can reach for it on their own using just one hand. And at the same time, kids will enjoy looking at large photographs of other babies teething on a rattle, bagel, biscuit, their own fingers and feet, a book, and a toy.
This book is horrible on its own, but particularly for the incredibly condescending note for parents inside the front cover. The author patiently explains that babies like to put things in their mouths, and while this book is completely non-toxic, "we would prefer" that the baby chew on the pretzel teether included. Like you would get to the point where you have a baby and it suddenly occurs to you "holy crap, this thing keeps putting things in its mouth! What does it mean???"
There is just something about the whole tone of this book that irritates me, but I think it probably has to do with that preface. This is a book that no parent would ever buy for themselves (especially because as babies of a certain age are almost addicted to pictures of other babies, if this book is in your house you will be required to read it over, and over, and over again). It's one of those books that people pick up on their way to your house when they suddenly remember that you have a baby and maybe they should buy it something. The best thing this book has going for me is that it's given me something relatively benign to complain about.
The cover states for ages 6 to 12 months. I would recommend from 3 months. While some older babies may enjoy this book it is not for toddlers. I think 3 to 9 months would be a more appropriate recommendation.