The illustrations in the book are all bright and colorful. They're also very easy for children to relate to. There's a lot of detail in the illustrations and my children had great fun pointing out various bits and pieces.
I read the book aloud to both of my children and they stayed attentive throughout. Best of all, it provided me with some great ideas and opened some enlightening discussion topics with them. It was interesting to be able to point to pages and ask them, "do you feel like that?".
I'd recommend Squirmy Wormy to all parents of children on the autism spectrum, with SPD or even with non-autistic conditions such as learning difficulties and ADHD. There are a lot great ideas in it which are suitable for a much broader range of children.
Professionals working with special needs children really need to grab a copy, too. If nothing else, it's the kind of book that they should have in their waiting rooms.