My wife has a book that is 97 years old (a book of Hans Andersen's fairy tales dated 1917) and we just realised the plates are by Heath-Robinson.
I suspect the plates are worth as much as the book. My wife took it off the bookshelf to read, thinking she might read them to the grandchildren.
The book was a gift from her Uncle Ernest to her mum when she was a little girl in the last years of WW1. The book binding is tatty now, but the fairy tales don't age. I hope the grandchildren enjoy it too. It will be owned by one of them soon.