The fun of this book is participating in the entertainment of trying not to yawn with your (hopefully sleepy) child. It is both light-hearted and funny. The little boy in the story provides lots of recommendations for how NOT to yawn. A clever idea that could easily be read over and over again, without the story getting tiresome. This makes it an ideal bedtime story because, as it explains, you have to go to bed if you yawn. This task is almost impossible to avoid whilst reading this book. I'm also a fan of narrators who address the reader, as this book does. It draws in the audience, and becomes a pantomime-like experience! I also like the fact that that, even though the main character is consumed with avoiding a yawn, he goes off to bed, quite happily in the end, which is the desired effect of course.
The illustrations are very simple and stylised, hand drawn and coloured digitally. Whilst they are very sweet and funny, with a wonderful contemporary colour palette, there is a lot of white space, and sparse details. In some books I feel this works admirably, particularly toddler books aimed at 0-2. Beyond that, I feel more details are always welcome in order to stand up to repeated viewings, and encourage more discussions and chats between the reader and the child.
I'd recommend it for any child between age 2-6.