Thinking 'outside the box' a definition for a book could be simple.. A container for marks which communicate meaning, in pictures, text or symbols..
I have started very small, and tentatively.
'ULURU' is a container made from the card cover of an Australian softback book. I constructed the cylinder and its lid, then painted it in acrylic paint with sand mixed in.
The sticks are cut to fit, and painted with symbols from the Native Australian people's myths and stories. See them as the pages of this 'book'. They are also symbolic of the Aboriginal memorial staves which can be seen in Australia. www.nga.gov.au/panos/LRG.cfm?MOV=MemPoles/Poles
I'm a celt, but several of my early years were spent in that beautiful country, and i claim an affinity with the place.