JR at Three Guys One Book has this to say:
The true test of any children’s book is how a child reacts to it. I read Billy Twitters and his Blue Whale Problem to my son twice this evening, and when I was done I started to page through it while I wrote this review. My son got out of bed and took it back from me and set it down next to him while he went to sleep. We’ll be reading this book for a long time to come.
Read the whole review here.