Tennis ball by Linda Newbown - what is a book?

I came across this unusual format for a book, i think it is very inventive and i think its interesting how a book can look like a book on the inside, with pages etc. but the way you bind it can disguise it.

Nebown talks about the book and what a book is in this statememt: (i think it raises some interesting questions for me to think about while i design my books)

The Tennis ball book was made in response to the dichotomy of book as object and book as information. A book is a difficult thing to define because half of it is object and half is an abstract concept. Is a book the sum of certain requisite characteristics? If a book has no pages is it still a book? If it cannot be opened is it still a book? These are the things I like to ask as I make my books. My artists’ books are a way of questioning bookishness.

(Artist statement sourced from State Library of Queensland, Artists’ books online, 2005)