The author and illustrator of the book “I used to be a fish” is Tom Sullivan.It is a book for kids that Grade 2-4. It is a book about a fish wonder about his evolution process.He went from fish, lizard to a monkey then human this book focused on evolution because every animal he becomes he turns into another.I like this book because we are learning the evolution in our science, also in this story we can know the simple evolution from it.Also the vocabulary is easy to understand.In conclusion,I think the illustrator of the book is very good, it can make you feel easy to understand and I would definitely recommend this book for little kids.